Umm...I'm probably not the best person for advice here, but I'm kind of in your same situation. Reggie and Smokey are both old dogs, and they don't like Nebo. They are ok with him as long as he isn't jumping/pawing/biting at him. Is Teddy ok with Chewy when he's calm, or do they fight even then? Smokey mostly ignores him, but Reggie growls ALL the time. Both have bit AT Nebo, but I don't think anyone has actually got hurt.

How bad is Chewy bleeding? I don't know much about pet first aid, so if it's too bad maybe you should take him to the vet. I would at least try to clean out the wounds with some water.

My best advice is that you're going to have to keep them separate. I let Nebo around Reggie/Smokey, but never alone. That way if anything really bad happens, I can be there to stop it. They really aren't too bad together most of the time, it's just when Nebo gets in his really hyper moods. Also I wouldn't let them eat in the same place, or anything like that. I know that Smokey was about 8 years old when we got Reggie as a puppy. Smokey HATED Reggie for quite a while.......they totally love eachother now....