So tonight for the second time in three weeks, we've gotten together with friends for a play date with our three year olds. Twice now my DD and her best friend, both three, have ganged up and picked on another child, who has always been very a very close friend. It has happened with two different friends. We don't know what to do. We don't know why all of a sudden they have started bullying and picking on the other friends. Does anyone have any experience with something similar? We have tried explaining that we don't treat our friends that way, but obviously that didn't work as they did it again tonight.