diff --git a/testing/btest/istate/broccoli-ipv6.bro b/testing/btest/istate/broccoli-ipv6.bro
index b7ab5bdb05..cd0b546ce7 100644
--- a/testing/btest/istate/broccoli-ipv6.bro
+++ b/testing/btest/istate/broccoli-ipv6.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-REQUIRES: test -e $BUILD/aux/broccoli/src/libbroccoli.so || test -e $BUILD/aux/broccoli/src/libbroccoli.dylib
 #
diff --git a/testing/btest/istate/broccoli.bro b/testing/btest/istate/broccoli.bro
index 235ff9119c..2bae5dc080 100644
--- a/testing/btest/istate/broccoli.bro
+++ b/testing/btest/istate/broccoli.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-REQUIRES: test -e $BUILD/aux/broccoli/src/libbroccoli.so || test -e $BUILD/aux/broccoli/src/libbroccoli.dylib
 #
diff --git a/testing/btest/istate/events-ssl.bro b/testing/btest/istate/events-ssl.bro
index 25aa2dc8fb..03784addef 100644
--- a/testing/btest/istate/events-ssl.bro
+++ b/testing/btest/istate/events-ssl.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run sender   bro -C -r $TRACES/web.trace --pseudo-realtime ../sender.bro
 # @TEST-EXEC: btest-bg-run receiver bro ../receiver.bro
diff --git a/testing/btest/istate/events.bro b/testing/btest/istate/events.bro
index 81a1d765db..81d9cc61b6 100644
--- a/testing/btest/istate/events.bro
+++ b/testing/btest/istate/events.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run sender   bro -C -r $TRACES/web.trace --pseudo-realtime ../sender.bro
 # @TEST-EXEC: btest-bg-run receiver bro ../receiver.bro
diff --git a/testing/btest/istate/pybroccoli.py b/testing/btest/istate/pybroccoli.py
index 1a5830b41a..9f26efca31 100644
--- a/testing/btest/istate/pybroccoli.py
+++ b/testing/btest/istate/pybroccoli.py
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-REQUIRES: test -e $BUILD/aux/broccoli/src/libbroccoli.so || test -e $BUILD/aux/broccoli/src/libbroccoli.dylib
 # @TEST-REQUIRES: test -e $BUILD/aux/broccoli/bindings/broccoli-python/_broccoli_intern.so
diff --git a/testing/btest/istate/sync.bro b/testing/btest/istate/sync.bro
index db5ea0bbb4..776ddfd2fa 100644
--- a/testing/btest/istate/sync.bro
+++ b/testing/btest/istate/sync.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run sender   bro %INPUT ../sender.bro
 # @TEST-EXEC: btest-bg-run receiver bro %INPUT ../receiver.bro
diff --git a/testing/btest/scripts/base/frameworks/cluster/start-it-up.bro b/testing/btest/scripts/base/frameworks/cluster/start-it-up.bro
index d7b552d962..a1069d1bd0 100644
--- a/testing/btest/scripts/base/frameworks/cluster/start-it-up.bro
+++ b/testing/btest/scripts/base/frameworks/cluster/start-it-up.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run manager-1 BROPATH=$BROPATH:.. CLUSTER_NODE=manager-1 bro %INPUT
 # @TEST-EXEC: btest-bg-run proxy-1   BROPATH=$BROPATH:.. CLUSTER_NODE=proxy-1 bro %INPUT
diff --git a/testing/btest/scripts/base/frameworks/communication/communication_log_baseline.bro b/testing/btest/scripts/base/frameworks/communication/communication_log_baseline.bro
index 85b23dbdc0..3d80ef7777 100644
--- a/testing/btest/scripts/base/frameworks/communication/communication_log_baseline.bro
+++ b/testing/btest/scripts/base/frameworks/communication/communication_log_baseline.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run receiver bro -b ../receiver.bro
 # @TEST-EXEC: btest-bg-run sender   bro -b ../sender.bro
diff --git a/testing/btest/scripts/base/frameworks/control/configuration_update.bro b/testing/btest/scripts/base/frameworks/control/configuration_update.bro
index d09105ca7a..920a162503 100644
--- a/testing/btest/scripts/base/frameworks/control/configuration_update.bro
+++ b/testing/btest/scripts/base/frameworks/control/configuration_update.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run controllee  BROPATH=$BROPATH:.. bro %INPUT frameworks/control/controllee Communication::listen_port=65531/tcp 
 # @TEST-EXEC: btest-bg-run controller  BROPATH=$BROPATH:.. bro %INPUT test-redef frameworks/control/controller Control::host=127.0.0.1 Control::host_port=65531/tcp Control::cmd=configuration_update
diff --git a/testing/btest/scripts/base/frameworks/control/id_value.bro b/testing/btest/scripts/base/frameworks/control/id_value.bro
index 7235521034..c5d1d063f5 100644
--- a/testing/btest/scripts/base/frameworks/control/id_value.bro
+++ b/testing/btest/scripts/base/frameworks/control/id_value.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run controllee  BROPATH=$BROPATH:.. bro %INPUT only-for-controllee frameworks/control/controllee Communication::listen_port=65532/tcp 
 # @TEST-EXEC: btest-bg-run controller  BROPATH=$BROPATH:.. bro %INPUT frameworks/control/controller Control::host=127.0.0.1 Control::host_port=65532/tcp Control::cmd=id_value Control::arg=test_var
diff --git a/testing/btest/scripts/base/frameworks/control/shutdown.bro b/testing/btest/scripts/base/frameworks/control/shutdown.bro
index ec1ca6da16..7b6e5713f8 100644
--- a/testing/btest/scripts/base/frameworks/control/shutdown.bro
+++ b/testing/btest/scripts/base/frameworks/control/shutdown.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run controllee BROPATH=$BROPATH:.. bro %INPUT frameworks/control/controllee Communication::listen_port=65530/tcp 
 # @TEST-EXEC: btest-bg-run controller BROPATH=$BROPATH:.. bro %INPUT frameworks/control/controller Control::host=127.0.0.1 Control::host_port=65530/tcp Control::cmd=shutdown
diff --git a/testing/btest/scripts/base/frameworks/logging/remote-types.bro b/testing/btest/scripts/base/frameworks/logging/remote-types.bro
index ce93495bc8..f1ef4f0c31 100644
--- a/testing/btest/scripts/base/frameworks/logging/remote-types.bro
+++ b/testing/btest/scripts/base/frameworks/logging/remote-types.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run sender bro --pseudo-realtime %INPUT ../sender.bro
 # @TEST-EXEC: btest-bg-run receiver bro --pseudo-realtime %INPUT ../receiver.bro
diff --git a/testing/btest/scripts/base/frameworks/logging/remote.bro b/testing/btest/scripts/base/frameworks/logging/remote.bro
index bb1e5b8ce3..8375d7915a 100644
--- a/testing/btest/scripts/base/frameworks/logging/remote.bro
+++ b/testing/btest/scripts/base/frameworks/logging/remote.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run sender bro --pseudo-realtime %INPUT ../sender.bro
 # @TEST-EXEC: sleep 1
diff --git a/testing/btest/scripts/base/frameworks/metrics/basic-cluster.bro b/testing/btest/scripts/base/frameworks/metrics/basic-cluster.bro
index b801074b33..09479b7a2f 100644
--- a/testing/btest/scripts/base/frameworks/metrics/basic-cluster.bro
+++ b/testing/btest/scripts/base/frameworks/metrics/basic-cluster.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run manager-1 BROPATH=$BROPATH:.. CLUSTER_NODE=manager-1 bro %INPUT
 # @TEST-EXEC: btest-bg-run proxy-1   BROPATH=$BROPATH:.. CLUSTER_NODE=proxy-1 bro %INPUT
diff --git a/testing/btest/scripts/base/frameworks/metrics/cluster-intermediate-update.bro b/testing/btest/scripts/base/frameworks/metrics/cluster-intermediate-update.bro
index 701d2ea378..654e42976a 100644
--- a/testing/btest/scripts/base/frameworks/metrics/cluster-intermediate-update.bro
+++ b/testing/btest/scripts/base/frameworks/metrics/cluster-intermediate-update.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run manager-1 BROPATH=$BROPATH:.. CLUSTER_NODE=manager-1 bro %INPUT
 # @TEST-EXEC: btest-bg-run proxy-1   BROPATH=$BROPATH:.. CLUSTER_NODE=proxy-1 bro %INPUT
diff --git a/testing/btest/scripts/base/frameworks/notice/cluster.bro b/testing/btest/scripts/base/frameworks/notice/cluster.bro
index 97470eaa7f..8d54a27eaf 100644
--- a/testing/btest/scripts/base/frameworks/notice/cluster.bro
+++ b/testing/btest/scripts/base/frameworks/notice/cluster.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run manager-1 BROPATH=$BROPATH:.. CLUSTER_NODE=manager-1 bro %INPUT
 # @TEST-EXEC: btest-bg-run proxy-1   BROPATH=$BROPATH:.. CLUSTER_NODE=proxy-1 bro %INPUT
diff --git a/testing/btest/scripts/base/frameworks/notice/suppression-cluster.bro b/testing/btest/scripts/base/frameworks/notice/suppression-cluster.bro
index d56d940e8e..b812c6451d 100644
--- a/testing/btest/scripts/base/frameworks/notice/suppression-cluster.bro
+++ b/testing/btest/scripts/base/frameworks/notice/suppression-cluster.bro
@@ -1,4 +1,4 @@
-# @TEST-GROUP: comm
+# @TEST-SERIALIZE: comm
 #
 # @TEST-EXEC: btest-bg-run manager-1 BROPATH=$BROPATH:.. CLUSTER_NODE=manager-1 bro %INPUT
 # @TEST-EXEC: btest-bg-run proxy-1   BROPATH=$BROPATH:.. CLUSTER_NODE=proxy-1 bro %INPUT