I agree that he definately
MUST learn to come to his name. It's for his own safety and also so he learns who's the boss. But I would start walking him w/ a harness on and a leash and do this by himself for a while so you can learn his spots of where he tends to like to "do his business". Kinda make a plan/schedule for him. And after a while I would begin taking him out w/ the other dogs (while he's still on the leash and harness) and whenever you notice him starting to act anxious/aggressive/ any behavior you find obnoxious and innapropriate just tug his leash a little bit, make him sit and focus on you.(keep eye contact). Once he quiets down you can start walking him again. (You can use small treats as praise or use clicker training.. very cool btw) And everytime he acts out make him sit and focus on you and just keep on correcting him. And eventually you will be able to let him out w/ the other dogs but no matter what I would always suggest staying out w/ them to make sure he doesn't revert back to his old habits. Good luck!
