I have three pit bulls in the house. 2 males and a female. I am not sure the ages or age difference of yours, but bringing in the new male was an interesting expierence. We introduced them on neutral territory to get a gage for their interactions. It was a little scary for me, But over time and some assertions from the oldest male everyone fell into place. I am sorry I dont have anything more for you. It took us time and patience. I had to pay close attention to the dogs and their behaviors/reactions. I wish you the best of luck.