I'm so sorry she's still causing such troubles. With as many cats as you have, you need harmony amongst them for sure.

Can you possibly try and find her a home where she is the only kitty? That way you wouldn't be giving up on her or feel like you're tossing her out. How is she with Scooter? Maybe if you close her in the bedroom with him for most of the time and only let her out occassionally?