Nearly there...
I put a new line in the surrender.sqs...
? side _Unit == west : goto exit
... and this seemed to do the trick. Now only the East units surrender.
I still have one more question though
Once the surrender.sqs has been activated, I want to begin a cutscene. How do I make the camera target the nearest
alive east unit (who is now surrendering)? In an ideal world it would be the nearest eastern unit to the player, but it doesn't have to be.
I can't quite get my head around the randomness of eastern casualties to work out how to target!
You've been most helpful so far guys... hope I'm not asking for too much.