Help me out

Well... First That friend who is pulling away one of your 프렌즈 is totally wrong for doing that.First Get That person Who IS Mean and look her in the eyes and stand up straight and say something like " Stop It, (Your 프렌즈 Name) Is my Friend! That Is Mean What 당신 Are Doing!Please Stop it!" then confront her. and tell your friend to ignore that person who is Mean
try to be 의해 your friend Alot so that mean person cant get to her. Hope That Helps , Good Luck! :)

If the friend who's being pulled away from 당신 didn't do anything wrong, then I would only be 프렌즈 with her. If she did, try to get her to apologize to the first one for whatever she did.

First of all, I would pull Friend 1 aside and ask her why she's doing it.
당신 might wanna ask her if anything is going on that 당신 might need to talk about.
Then, if she says nothing is going on and that she just doesn't like Friend 2, then I would tell her that true 프렌즈 wouldn't be so selfish to keep a friend to themselves.
If she keeps doing it, stop being 프렌즈 with Friend 1 and keep 의해 Friend 2's side, staying as strong as 당신 can for the worst.
Things might get ugly between 당신 and Friend 1 if 당신 don't keep 의해 your friends.
Hope that helps. ^^