[MyTrixie143]

Aww, they are all soooo cute!! Try not to stress about it, he'll come around eventually. I remember when Hershey joined my gang, the others shunned him for about a month. Heck when Brownie joined the gang which was much smaller then it took a few months before they accepted him. They all get along great now. This happens every time a new member joins the family, well except for Gracie she was accepted right away. I've gone through this many times myself, it just takes time and patience. He will learn to accept them and take an interest in them when he is ready.
The fact that he isn't growling or being territorial to them is great progress, not all dogs start off that well. Just keep doing what you are doing and he will come around when he is ready and then they all will be the best of friends.