The group idea looks like a good start.
Only problem is this loading script will need to work multiple times and needs to work on ANY civy on the map for ANY vehicle on the map. I have tried the action "getInCargo" way which at least plays the animation of them moving to the vehicle.
And how how do I get them out again though? I'm thinking of the moveOut command along with disableAI "move" to get them out and make sure they don't get back in.