I feel so stupid and so sorry for her?

There's this girl who is the kindest person I have ever met. I am quite good friends with her, but unfortunately, she's not in my friendship group. She seems very lonely, so I have been hanging around with her at lunch and things, and trying to get her in my friendship group. But my friends keep taking me away from her. I didn'tknow whether they liked her or not, so I asked one of them on FaceBook, "Do you like ....." My friend replied, "Wtf what kind of demented question is that." And then the conversation ended. I kind of don't want to hang around with them any more, as some of them are such idiots and this girl is so nice. I am so stuck.