Two separate stages, or areas might work... otherwise, handing instruments to one another and getting the drummers swapped over could be, umm, interesting... and they'd need to rehearse the heck out of it to stand any chance at all, imo.
If they DO decide to go with it... please say you'll video at least the change-overs for us!
If they DO decide to go with it... please say you'll video at least the change-overs for us!