How to deal with friends like these?

[Mrs. Oliver Wood]

For anonymity sake, -rolls eyes- let's call them Airyauna (air ee awn ah) and Charlotte. Airyauna is 2 years older than me, but a grade below me. Charlotte is 2 months older than me, a grade below me and same grade as Airyauna. The three of us are friends. Problem is, when one is with me, they'll trash talk the other, and talk highly about and to me, but when they're together or with their other friends (I'm not in their group of friends, we don't get along) they'll trash talk me both behind my back and around me. They only stop if they see me with another one of our mutual friends (Tyffanii) because she's threatened to beat the group leader up if they don't leave me alone.

The group (minus Airyauna and Charlotte) have in the past; repeatedly false flagged my facebook, YouTube channel, Tumblr and attempted to hack my AOL and iCloud email accounts.