Am I correct in thinking that you want the patrol to return to safe mode after the end of their firefight?
If so, here's what you do. Create a trigger, repeating, West (or whoever the enemy is) not present. Use a script or gamelogic loop to attach the trigger to the leader of the patrol group. The trigger will look somethng like this
Area: experiment. maybe 150x150
Activation: West not present Repeatedly
Condition: this and trig1On
On activation: trig1On=false; leader patrolGrp1 setBehaviour "safe"
The variable trig1On is set to true (by the script or another trigger) when the patrol has a contact. This is not at all guaranteed by the way, I'm just making it up.