4 dogs fighting? Are they trying to establish a pecking order ???

You need to be the Alpha Dog and so does your neighbor. Do not let them get to that stage. Let them learn that if it's not OK with you then it is not going to happen. In order to do this you MUST find a form of discipline that works with this pack and stay on top of it. I don't mean yelling or hitting the dogs, this type of behavior does more harm then good. Watch them closely, if you see any sign of aggression correct it immediately. After a few days of this they should get the idea... GOOD LUCK!!!