I'm sorry your household has become so disrupted. Silly kitties!

Becky and Abby were separated for almost six months after Becky decided to "go for" Abby. Skipping the details of why Becky did that....Abby wouldn't come out of the bedroom for three months. We kept the door closed while we were gone and I think she liked it. If the door was open, she would only focus on whether or not Becky was attempting to get in.

After three months, Abby started coming out and we always supervised.

It seemed like after five months or so, Becky lost interest in terrorizing Abby.

I no longer believe in "letting them work it out themselves." We break it up if they're being bad and they do know they're being bad, just as if they're jumping up on the cupboards.

We also have Feliway plug-ins upstairs and downstairs. We purchase them in quantity off the internet. I can tell when they need a new refill because they'll start the hissing.

Have you thought of using Rescue Remedy? The good thing about Rescue Remedy is that you just put it in the water. I think some others have had good luck with this.

Good luck to you and your family!