Dd is in Y8, goes around in a group of friends, about 10 of them (girls and boys).
Very easy going, no exclusions, no pettiness, no jealousy, (very very lucky I know).
A girl called X has been an on and off vistor to the group, now more on than off, and is causing all sorts of ructions. Where before there was light hearted ribbing,non-malicious, she is being openly bitchy, trying to cause ill-feeling, very needy, moody, controlling...
Already one of the group has gone off with other people as she found it all too stressful, another now spends lunches in the library just to get some peace.
Dd and 2 of the others would always walk home and gently mull over the day, she is there generally causing ill-feeling.
Dd has tried t like her but she is getting so fed up with the constant attempts of X to be her partner, be her "best friend" (dd doesn't and never has wanted one best friend) and to try and turn her against others in the group.
She doesn't like confrontation, but it steaming by the time she gets home.
Any ideas how to deal with it. She wouldn't tell her to F* off I know although she does say "X don't be mean to Y" or "well they're my friend even if you don't like them"