one jerk of a quail helppp
I think the advice I usually hear in this kind of situation is to remove the offender for a few days and then reintroduce her. Being a flock animal, the separation might make her realize the others are not just in her way, it's actually better to have them than to live alone. And removing and reintroducing her will make her the 'new one' in the cage and automatically put her at the bottom of the peck order (though she might peck her way back up right away if she didn't learn her lesson). As to how long the 'few days' should last, I'm not entirely sure and it might vary from case to case. I would try about 5 days and see if that helps.
Definitely try taking her out for a few days, but keep her close enough so they can see each other as it makes the others more accepting when reintroduced. Often works but not always. We had a hen that kept attacking the others, even the male, but would always come off second best. Despite this she kept attacking everytime we reintroduced her. Like she had a death wish! So we ended up selling her.