Not all horses react this way. It takes a simple look, pin of the ears, lift of the foot, stomp, bare of teeth, or threat with the back end for another horse to take the hint. 9 times out of 10, these behaviors are demonstrated as opposed to a full fledged kick. Just MHO.
And personally, I wouldn't have my horses that were most conflicting together and with shoes on their back feet. I would either separate them, turn them out at different times or pull the back shoes. The point is, avoid such a possibly dangerous situation.
Out curiosity, why does your draft have shoes anyway?