What is important to him? Food? Toys? Walks?

Whatever it is, be sure he gets it first. You probably already know which situations he is more controlling in. As long as he doesn't get nasty about it, just let him be first. First through doorways, first outside, sleeping higher or in a better position, etc. Watch how the other dogs react and see if they are okay with it.

This may or may not work. It usually does work though so it is worth a try. Good luck