Here's a demo mission
showing this at work.
Set up three MOVE waypoints and a fourth waypoint of type CYCLE near where the helo starts. This will be the patrol path. Then setup a SAD (Search And Destroy) waypoint past the CYCLE waypoint. We'll move this waypoint when we detect BLUFOR.
The triggers for the detection should have this as their OnAct:
[group hind, 5] setWaypointPosition [position thisTrigger, 0];
That will move the 5th waypoint of the helicopter (0 = placement, 1-3 = MOVE, 4 = CYCLE, 5 = SAD) to the position of the trigger.
For the demo mission just use your radio to start a BLUFOR attack on three patrolled towns.
Note that the waypoint will move to the latest trigger that activated if more than one do.