WOW!! What a story. This will sound strange coming from me but even though I think Betty is a horse's ***, there's nothing you can do unless Amanda stops engaging at the provocation. Encourage her strongly never to respond and if there are witnesses then to respond in a frightened manner. Betty will be the one leaving. Maybe her pdoc can give her something to calm her down. I'd hate to see her lose where she lives over Betty's nonsense. That's basically what Betty wants. Best wishes and let me know how it goes. Another path might be getting them to sit down and have a heart-to-heart and work it out. Just a thought.