I'm sorry to hear that you're having problems. I know it's also hard to give cats their own space when you live in small apartment. I've used both the plugins and the spray and it helped at first but later on it seemed like they became immune to it so it didn't work as well.

I also know how females can be and even though I love Pearl and Ziggy, I've already told many people that I won't be adopting any more females because they're too territorial, bossy, and can be down right mean to their male siblings for no reason at all. My males are much more laid back and loving. I hope you can find something to bring some peace to your household. Good luck.