Hi M.!
I knowwww!! Some kids are just soooo "mean". We had somewhat of an issue with "not so nice" kids. My son is a very sweet, kind, friendly boy, so when he told me one kid wouldn't let him play with the rest of them I was upset. He did have a few really great friends but this one boy was just not "nice" to him and seemed to be singling my son out of recess games. Well, I visited my son, unannounced, during lunch and ate with him. I met all the children and they seemed to be "impressed" that "Connor's Mommy" came for lunch. They all wanted to meet "Connor's Mommy" and our school even allows for us to watch them play at recess. Well, during recess I did notice how some boys played "ball" in one corner, while some were left out. So, I walked over to my son and asked why he wasn't playing and he said that this was the game "he was not allowed" to play because of the one boy. So, I said, "get the rest of your friends and let's start our own game!" The boys who were not playing now started a game with my son and were having a great time. I sat back down and watched. In no time, the "other" boys and the one boy who did not want my son to play was asking to play with my son and his friends. My son, who has always been told not to exclude anyone, said "sure" and next thing you know, they were all playing together. Yay!! So, maybe just a little intervention on your part may change their behavior. Visit the school, help out in class and you'll be able to see what areas and behaviors need to be tweaked. It's also great just to get to know your Daughter's friends and you may also meet their Mommy's, too.
Take Care and Good Luck!
D.