Today all three girls came with me on a walk. We wanted to get some leash training in before it got too hot. The drills are the same no matter how many I have. We SIT at every mailbox. I test their self control together. Then we always end with a DOWN in the driveway when they are tired and ready to relax. I add distance one day at a time. The goal is to get to the trash can with the poop bag while they stay put! Expect the behavior you want and you will get it with practice & patience!