stealing friends?

SO this group of girls and my group of friends don't really get along at school. Well, not too long ago there was a new girl, and the teacher ask someone to be her buddy so that she's not alone. One of the girls from that group volunteer to be the new girl's "buddy". But after a day when the new girl have class with my friends and I, she started to hang out with us.Although i don't like that group of girls, i try to not cause any problem with them. And now, i'm scared that they will think we "stole" their new friend on purpose or something. I know we aren't little kids, and there is really no such thing as stealing friends but i don't know :(. I even talk to my friends about it, and they said it's the new girl's choice to choose who she wants to hang out with and that if the other group of girls think that, it's their problem?