What do I say to her?

So I'm having a small get together at my house, around 6 people including me. I started by inviting two girls, girl A and B. Eventually I found out from B that both of them aren't on good terms. I asked A and she said that she felt like I didn't need to know even though I told her I invited girl B.....blah blah blah.... the story has no big part to the whole, so girl A ended up saying "if we both go we both go, we'll both have to deal with it, you don't have to do anything"

I told Girl B what she said and she replied "hah well if she wants to go, i'll stay home. no big deal."

The problem is I like girl B what can I say to convince her to come instead of girl A, and I don't want to sound desperate

I tried to descirbe it the best I can, if you need any more info that could help I would gladly reply

I don't know how "close" friends you are with Girl B and A but this is how I would try and solve it.
Just tell girl B that you would realy like if she come. You don't need to sound desprate just be straight forward, and tell her that she doesn't need to say anything to girl A (since there are more people then just the 3 of you girl A would have other people to talk to then you or girl B.)
Tell her also that all your attantion would go to her and that she would make you very happy when she would come.

If this doesn't work and you realy like the girl ask her out another time where it's just the 2 of you.

I hope my advice will help a little.

Something like, "Well, Girl B, I understand why you wouldn't want to come to the party, but between you and me, if I had known before that only one of you would come, I'd rather have just invited you. Maybe we can get together some other time."

Eh?

Sorry you Invited both of them you'd be a jerk to diss invite