"They ditched me when I wouldn't side with them!"

Last year, I was really good friends with these three girls. We were all really close, even though two of them really didn't like my other friend. When I went on vacation, they all got into this really big fight. Two of the girls wanted me to be on their side when I wasn't even involved in any of it! I got really annoyed that they were picking on and being jerks to my other friend, so I asked them why they couldn't just be nice to her. They teamed up against me and wouldn't talk to me for about two months. I really didn't get how someone so close to me could be so mean. Next thing I know, they tell me they don't want to be friends with me anymore. I haven't talked to them since.