Getting 2 dogs to be friends?

Hi,

We have someone's dog (Not ours, and the owners are not at their house, his name is supposedly River) and we also have 2 of our own dogs. Our female (Brandy) gets along with River, and he does too. Our other dog (Rex) gets along with him, however River does not. From what my dad told me, River tried to bite Rex, but Rex wanted to play...

We're not sure how long we have to take care of River, we left messeages and a note at their door, and are now waiting...

Would anyone know how to get these 2 dogs to stay with each other?

Well, it's too late to introduce them on neutral territory now! As long as they aren't fighting enough to draw blood or anything, I'd let them work things out between themselves.

River's owners came back and took him, and told us that he doesn't really get along with other male dogs, because of an accident when he was young.