I think that this is a marvelous opportunity for your daughter to meet new people and make new friends! Not only that, but you will be teaching her one of the best lessons you can possibly teach your child - you cannot always get what you want.
Instead of making a fuss and pushing for getting her on the same team with her friends, make a point of being accepting of the circumstances, and show her that being pushy to get your way is not the best way of doing things.
Too many children these days are just totally spoiled. We give in to everything, and then also show them that by raising a stink, we can get our way...well, that is just plain bad. I think it would be very admirable of you to get her in on another team, and show her that she can have fun and make new friends, and learn that lesson. She might not actually know that it is a lesson right now, but enough of these types of situations will, over time, teach her that life is full of minor disappointmens, but that you can make lemonade out of all of those little lemons, and may end up actually enjoying it very much.
It is a life lesson that our own mothers taught us, but that sadly, many of us are not teaching to our children. I truly think that we would have far less crime and fear in our nation if we would just think about how our parents and grandparents were raised, and try to do the same for our kids. Disappointment never hurt anyone in life, but constantly being given everything you ever wanted has led to our nation being the way it is right now.
Ok, enough about that. Whatever you decide, I hope your daughter enjoys herself and makes lots of new friends.