My best friends hate each other?

I have been hanging about with two girls, Stacey & Carla since we all started in Primary One. S & C both knew each other since nursery and generally got on really well, but just recently (we're in Primary Seven now) Stacey fell out with Carla and they had a major bust up on Facebook and fell out for a few weeks. Both of them were a nightmare towards me trying to get me to pick sides, they fell back in about a fortnight after the fall out and we were back to our trio but about a week ago we were doing an exercise in PSD where we had to pair up with a partner and Stacey picked a girl who none of us have ever really got on with who sat at her table. Alana (the girl) said that Stacey was her BF and Stacey said the exact same. When I got home, I went on MSN and Stacey's PM was: Stacey loves Alana(YN) Besties forever(L) and suddenly I got a chat request from a group on MSN consisting of Stacey, Carla, Alana & another girl who is our friend, Catie. Stacey and Carla were basically having a fight in caps lock and Alana was joining in when it had nothing to do with her. Eventually Stacey typed in caps lock 'OH FECK OFF I'VE NEVER REALLY LIKED YOU OR EVIE' I was really hurt at that. The next day at school Stacey and Alana hung out at playtime and lunchtime and I hung out with Carla. I told her to leave it, that Stacey would figure out Alana in her own time but since Alana was sniping at Carla, she said some horrible things about Alana and Stacey at the same time. Stacey spoke to me on Facebook that night saying she didn't mean it and she still loved me as her number one best friend. The next day Stacey and Alana fell out and Stacey was all alone, I told Carla to make up but Carla was still really annoyed at Stacey so refused, I said I would still be Stacey's friend regardless of what she thought so I made up with Stacey and Carla stormed off in a huff. Stacey's been trying to get me on her side and doing some really malicious things on Facebook like commenting on all Carla's photos with rude things about her and some horrible blonde jokes (Carla's blonde) and Carla has been saying simaliar stuff about how Stacey was a friend stealer and trying to get me on her side. I love them both equally and I can't say I'm on Stacey's side or I'll lose Carla, and I can't say I'm on Carla's side or I'll lose Stacey?! I just want them to get on like they used to! Is this too much to ask? Any idea how to make them fall back in?