[Unit]
Description="Group service"
After=test-worker@a.service test-worker@b.service
Requires=test-worker@a.service test-worker@b.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true

[Unit]
Description="Worker service %i"
PartOf=test-group.service

[Service]
Type=simple
ExecStart=/opt/bin/run.sh %i
Restart=on-failure

systemd[1]: Started "Worker service b".
systemd[1]: Started "Worker service a".
systemd[1]: Starting "Group service"...
systemd[1]: Started "Group service".
systemd[1]: test-worker@a.service: Main process exited, code=killed, status=9/KILL
systemd[1]: test-worker@a.service: Unit entered failed state.
systemd[1]: test-worker@a.service: Failed with result 'signal'.
systemd[1]: test-worker@a.service: Service hold-off time over, scheduling restart.
systemd[1]: Stopped "Group service".
systemd[1]: Stopping "Group service"...
systemd[1]: Stopped "Worker  service a".
systemd[1]: Started "Worker service a".
systemd[1]: Stopping "Worker service b"...
systemd[1]: Stopped "Worker service b".
systemd[1]: Started "Worker service b".
systemd[1]: Starting "Group service"...
systemd[1]: Started "Group service".