I had the same thing happen with my 2 boys. They kept getting worse and worse and I tried all sorts of things short of prescription drugs. I ended up keeping one of them in a big cage at all times (they each had a 12-hour shift) while I tried to convince my parents to take one of them. They have Havoc now and he's very happy to be the only kitty. He's a neurotic little thing and whenever he had one of his freakouts Toby would attack him (actually Toby would attack ME, as I was trying to grab either one of them to put in kitty time out)

Glad your girls have settled down though. Hopefully they will remain tolerant of each other