Separate them, and keep them separated. If possible, have at least two barriers between them, but always have at least one. It's a royal pain, but it beats vet bills (best case scenario) or a dead dog (worst case scenario). I've had to do it twice now, and hope to never have to do it again.
You may need a referral from your regular vet, but it's possible to find a behaviorist who can do phone or video consults. Probably the best place to start looking is the American College of Veterinary Behaviorists website. American College of Veterinary Behaviorists
You may need a referral from your regular vet, but it's possible to find a behaviorist who can do phone or video consults. Probably the best place to start looking is the American College of Veterinary Behaviorists website. American College of Veterinary Behaviorists