This will not help you in any way Johnnyboy, but I think you are on an interesting topic.
Ideally, the AIs reaction to different situations, should take their main objective into account.
In your case: getting the convoy through the area, no matter what.
Your problem is the same as I've always encountered in mission editing, where i wanted the enemy to brutally "storm" enemy positions, without care for life and limb, just moving forward. That is equally hard to achieve.
If there was some kind of objective/survival priority percentage, built into the game, this could be possible.
Maybe some scripting guru can create a good workaround for this behaviour.
Laggy
P.S I see that Inkompetent is reading this thread... he seems quite good with fsm scripts, maybe he can do it, I would ask him nicely. D.S