I have two basenjis - male and female, and a young mixed breed female. My basenjis lives on separate floors. The male was the first in the house. A year later I got the female so he would have a playmate and all was fine at first. But slowly the female started bullying him. I wish I had been more aware of it at first - I might have been able to intervene before it escalated to where it is now, but I can't let them in the same room. I'm convinced she would kill him if she could. He's terrified of her and not much of a fighter. She can be fierce. They both got along with the new dog at first, but then Rose started picking on her a bit. The luck here is that Gracie weighs 20 lbs more than Rose. She'll never start a fight, but can always stop it. As a result, Rose has learned not to pick on her, but she also won't play with her now that she's full grown because Grace has become too much for her with the size difference. The both played with Grace when she was small.
Because I have a multi-floor house I've been able to manage things with gates. I love them both so much that I didn't want to part with either of them. I will enjoy it, though, when the gates can come down.