Don't give her the hope that you are interested in her. Some
girls don't really catch hints well, so you have to find some
opportunities to say that you treat her as a friend. Don't overdo
it, as you will hurt her.
You can try this though. When she asks you, ask her to bring along
some friends and you bring some friends of your own. Best if all
know each other for some years. Just say the more people, the
merrier it is. No need to cook up some funny reasons for it. As
time goes by, hopefully she will catch this hint. If not, you got
to tell her directly, which is hurting.
Don't take any girl as your shield and says she's your girlfriend.
You will hurt both parties.