I have 3 best friends; Sarah, Millie, Emily. I've been best friends with Sarah for 14 years, Millie for 5 years and Emily for 2 years. Despite our ups and downs, I love them all very much and I don't want to lose them. But here's the problem; only recently my best friends Sarah and Emily started growing apart and now we are all forming separate groups :'(
This is mainly because Sarah keeps excluding Emily (not speaking to her, inviting her to schoolies at the end of the year or to her 18th in November) and Emily doesn't know why. Basically it's because Emily can sometimes get annoying (not like 'in your face' annoying but in general). Even though I'm hanging around with Emily for the past couple of days, I do not intend on picking a side. I've been very careful with what and how I say certain things to her because somehow I know it can travel around and can possibly travel back to my other group of friends. I haven't told Emily the reasons behind it, mainly because I don't want the fighting to continue. So now I'm stuck between both Emily and Sarah and I don't know what I should do? I feel sorry for Emily. I have told Emily to speak to Sarah about it but she doesn't want to because she knows that she hasn't done anything wrong. What can I do? I want them all to get along again like the old days.

They are kinda forcing me to choose between them...Sarah asked me a while ago to go to schoolies with her and Emily asked me recently to go to schoolies with her. I agreed to go to schoolies with Sarah and then I agreed to go with Emily. And I don't want to let anyone down or hurt them. I don't know what to do...
I am 18 by the way.
Yeah, I haven't been making up stories or anything between them. It's actually a lot more complicated than you might think.