Jim
I think you have several options here. I agree with Scott that you shound not go back thru the transom but out the side with their own separate drains. Yet you could do as ScottM has suggested and tie into the floor scuppers (see pic)
Come to think about it, if your plans include a live well in the transom you could Tee them into the bait tanks main drain and have all water exiting out through one hull fitting
