Stop AI from using transport

[Blockhead 10]

Im making a cooperative mission where you are lead by an AI character, he drives the car to a certain point and then everyone is suppose to get out and follow him on foot. I am not using the in game waypoint system, Im doing it all using trigger executed scripts. Ive gotten the AI to make all the right turns and when the vehicle gets there everyone is ejected and the car is locked. Problem is that he always orders everyone to get back in and then all AI units are able to bypass the lock aswell. How do I keep them from trying to use the car without blowing it up or whatever.

[ffur2007slx2_5 11]

{UnassignVehicle _x} forEach (units group this);