I agree with what has been written here. It totally depends on the individual dogs. I have an intact male wolfhound and 2 neutered males, pyr and TM. They all get along just fine. ChiChi my only female has also fit into the mix just great. Cody is my alpha and tends to break up fights, when they happen, very rarely. Once all the hierarchy is worked out between them, I don't think you will have problems. I took Cody and Max to meet Jake, prior to getting him. He jumped into my jeep and refused to get out. I loaded them up with him and they all stretched out together and went to sleep. We had a 2 hour ride home, so I wanted to make sure all was well, before we got on the road. If they had not been okay with him, right off the bat, I would not have him. It is all about what you are comfortable with and how the dogs handle each other. In other circumstances, Jake might have been a problem, but with Cody, he is submissive. Keep in mind that a rescue group telling you a dog is submissive or dominant does not mean that will be the same in your home or with your dogs. Cody was extremely submissive in the foster home, but has taken over my pack, completely. It all depends on the personalities involved.
Kathy