diff --git a/tests/t_client.rc-sample b/tests/t_client.rc-sample
index 4c87436..defa4aa 100644
--- a/tests/t_client.rc-sample
+++ b/tests/t_client.rc-sample
@@ -31,6 +31,21 @@
 #
 # tests to run (list suffixes for config stanzas below)
 #
+# The general idea is to use one number per server, so
+# e.g. use 1 for all tests talking to a UDP server, use
+# 2 for tests talking to a TCP server, and 3 for tests
+# talking to a P2P server.
+#
+# The indivdiual tests should then be indexed by using
+# letters.
+#
+# If you set TEST_RUN_GROUP=<number> then t_client.sh
+# will only run tests starting with that number. So
+# e.g. setting TEST_RUN_GROUP=1 will run 1 and 1a, but
+# not 2. This can be used to excercise only a specific
+# server, or to run tests against separate servers in
+# parallel.
+#
 TEST_RUN_LIST="1 2 2n"
 
 #
diff --git a/tests/t_client.sh.in b/tests/t_client.sh.in
index c3a9655..0568007 100755
--- a/tests/t_client.sh.in
+++ b/tests/t_client.sh.in
@@ -82,6 +82,21 @@
     exit "${TCLIENT_SKIP_RC}"
 fi
 
+if [ -n "$TEST_RUN_GROUP" ]; then
+    FILTERED_LIST=
+    for test in $TEST_RUN_LIST; do
+        group=$(echo $test | sed -E 's/^([0123456789]+).*/\1/')
+        if [ "$group" = "$TEST_RUN_GROUP" ]; then
+            FILTERED_LIST="$FILTERED_LIST $test"
+        fi
+    done
+    if [ -z "$FILTERED_LIST" ]; then
+        echo "Filtered TEST_RUN_LIST empty (group=$TEST_RUN_GROUP), no tests defined.  SKIP test." >&2
+        exit "${TCLIENT_SKIP_RC}"
+    fi
+    TEST_RUN_LIST=$FILTERED_LIST
+fi
+
 # Ensure PREFER_KSU is in a known state
 PREFER_KSU="${PREFER_KSU:-0}"
 
@@ -121,6 +136,9 @@
 fi
 
 LOGDIR=t_client-$(hostname)-$(date +%Y%m%d-%H%M%S)
+if [ -n "$TEST_RUN_GROUP" ]; then
+    LOGDIR="${LOGDIR}-${TEST_RUN_GROUP}"
+fi
 LOGDIR_ABS="$PWD/$LOGDIR"
 if mkdir $LOGDIR; then
     :