Im thinking making the original body invincible is probably the best way to go. Thankfully since i was using Invisible Woman i just made myself invisible and started possessing enemies, lol, that was the only way i could get my teammates to stop hitting poor IW.
Also while trying it out i got stuck in this horrible loop, so once i possessed someone and they died the possession jumped to another enemy. It kept going like that until no more enemies were around, but IW woman just kept doing the attack. It no longer does that though.