What should I say..?

I already asked tis question in another section, just wanted more replies.

ok, so my and my best friend are kinda having issues with quite a good friend of ours. Shes been forcing herself into a 3 with us for a couple of months and at lunch, she always expects us to meet her in oour form room and when we go out, say to the canteen or just for a walk around the school,she demands to know where we've been.We cant even talk about anything anymore without her interrupting and we dont really feel as comfortable discussing personal problems with her. We really want to stay friends with her, but she is driving us crazy, so we want to say something politely. The thing is, we think that she thinks we are her best friends, and is always trying to make a 3. And two's company, three's a crowd. What should we say to her so she understands how we feel, without wanting to be mean? because she is still my friend, and i want it to stay that way.

I had a situation like this at school and my friends handled it really badly!they basically told her that she was crowding them and it kind of sounded like they didnt like her!Its a really hard situation as if you try and do more things as a 2 you say that she practically questions you over where you have been!
It just sounds to me like she is really trying to belong to a group which is always quite difficult if theres already good friends in the group as no one really likes to have to share their friends!
The most obvious thing to say is to sit her down and talk to her about it but that will only make the 3 of you feel uncomfortable, so maybe over lunch or a shopping trip or something try and let her know that you are kind of used to being a 2 and you have a kind of routine thats shes not quite a part of yet!

Don't exclude her if she is your friend. That would be cruel. If she doesn't have anyone else to hang out with, put up with it. Put yourself in her position. How would you like to be treated like that?

what ever you say to her don't be too harsh.
i know what its like to be that third person, she has probably already realised that you don't always want her there, but maybe she has no where else to go and she doesn't want to spend lunch times alone...