Take some some to talk to your friend. Tell her that everything your other friends said is not true. Make her realize that you really want to be her friend again. Also ask her for a second chance, so you can prove to her that your an amazing friend. If your friend agrees to be your friend again, you should go up to your other friend's and tell them that nothing can come between (name of friend) and I.
ignore do the same
Get used to it, it happens in life.
It is quite normal for a friend to talk about other friends and thus, if you have other friends feel free to talk about them. If your friend is simply talking about friends and then waiting for a reaction from you then ignore it. Continue on with your other friends and don't worry too much about this friend and what they want to discuss.
Try talking to he/she maybe you all 3 will become the best of friends
Try to get along, or just pick a fight and get your others on your side, catch him talking smack about your other friends and tell them
To break, as a law or promise is to violate something. EX: Telling your friends a secret was a *violation* to your other friend.
Convince your friend to stop doing drugs - if necessary (and you should probably do this anyway) by telling the police - by talking to them without your ex-friends present; it will also help to get your friend doing other things instead of hanging out with the others, like sport or spending more time with you.
Leave it alone it will all work out by itself
This friend that you speak of, doesn't sound very trust worthy. You could talk to your friend, tell them that you don't appreciate them telling your other friends your personal things. That when you talk to your friend you're confiding in them and trusted that they wouldn't tell other people what your thoughts. Something to that extent. Or you could not trust that your friend will keep your thoughts to themselves and stop telling them your personal problems. These are mere suggestions, but I hope that my advice helps you out. If you'd like to talk you can message me if you'd like.
Ask your friends to put her in check the next time she starts talking crap, have them push her to tell you. If that isn't an option, or she refuses, or they refuse, your best bet is to point out the next time you two are hanging out that you can't stand people who talk behind other peoples backs. It'll work best if you stop her in the middle of talking bad about someone you both don't like but you've faced and she hasn't..
because you want the attention from your friends, and dont like it when its taken away.
If they don't acknoledge you as a friend, then get a new group. And if you think they are lame because you can't make them laugh other than telling jokes then find someone of your friend standards. Hope it helps~