You can order one of your squad mates to getin the tank as a driver and then order him to different places. But he won't fire, since he is the driver. I suppose you could make a script that would monitor the driver. If he "knowsabout" a target, the script could switch him to the gunners position. Of course, the tank would stop moving.
:hmm:
That may not be such a bad idea. You could end up with 12 tanks in your squad.