Not sure of the best response but here is what works for me when my buddy already has the upper hand by dominating the conversation at a bar. There is a reason these girls are talking to you. They like either you or the other guy, maybe both. So you have to find out if you have a chance still and go from there. Instead of just standing there with your dick in your hand, watching your friend talk, you have to make a break and take action. Get up, say you are going to head over to the bar ask each person individually if they want something. Your friend will say no, they want you the fuck out of there. Best case one of the girls offers to go with you and you make a break for it. Worst case, they barely acknowledge you and you have already lost them, look for someone else. Hopefully you land somewhere in the middle where a girl asks you to bring something back. When you come back with the drink you open things up where you are back at the focus of attention at least for a few minutes and from there you have to follow through to get yourself back in the running. Works at other places as well: museum - break and ask if anyone wants to go on the tour with you. Gala or social event in a great venue - break and ask if anyone wants to check out the great view from the courtyard or balcony. Festival - break and ask if anyone wants to check out one of the other stages with you.

Lastly, the girls need to be 8s to 10s. Other women will notice you with them and the mere fact you are able to pull them in, gives you a great chance to pull in any other woman at the venue. So ditch the friend and the girls if you aren't getting anywhere and find the others.