most of the time it will be ok to let them out together...but every once in a while you might have a dog or 2 jump and whip a young dog that hasn't learned the ropes...if your hunting buddies have these type of dogs then don't turn your young dogs loose until all are ready to start hunting...this gets the dogs minds on hunting and all should go smoothly...having the dogs mill around while gearing up could be trouble...I would do this way a few times until the dogs know each other...
Couldn't have said it better myself, i've never seen two dogs that were huntin and busy fight, its the slack time in between that will cause problems.
"the sun is shining somewhere in texas" -Jason Boland