Ask your buddy out as well, he can do you a favour and entertain a grenade (btw tell him that, don't trick him into it), if her friend desides to drop out tell your buddy to drop out.
Belive me, watch this going-indirect-vt96076.html you know why she brought a friend, she knows that you know, she knows why you'll bring your friend with you and in case that her friend drops (and you know why she'll drop), she'll know why your friend will drop, I know it sounds complicated, but that's why it's called "the game".
Altough I would give you a general advise, don't fuck your SPAM, that's when things get really complex
