Dice your thinking about it the wrong way. Its like going out to the bar with all your guy friends. Your acting like your going to go talk to this HB and not talk to your friends again that night. No one says that you have to hang out with the HB all night. Its actually probably in your favor to leave and go back and hang out with your friends for a little. One of the things is saw by Mystery was to wear something you can leave with her and tell her that you are letting her borrow it and you want it back the next time you see her. This will giver her something to remember you by and she will think about you the rest of the night and then when you do come back you already have a way to reengage the conversation and have the added bonus of the fact that she has spent the last hour thinking abut you. The other thing you can do is number close and set up a time to hang out when your out with just the guys who are hoping you get lucky and don't come back the rest of the night.