Yuck canned openers hate them way to much, a great opener I usally use is
as you aproach a 2 set or 3 set you will see the person holding the highers social value in the group (usally the one talking aloud, making the set laugh)
and as your about to enter you go
NO WAY thats true..when did that happen?!
considering girls gossip or talk about them doing something this a good hitter

she'll either respond
"yeah it happend"
then its easy from here!
just ask a few questions share something incomen, like my set last weekend
2 girls one hb8 and a hb7 were talking about something, so as I pass them I overhear something the blonde said, so i pass them by half a meter and turn around and said
"No way, is that true?"
so here its sink or swim, if she goes "go fuck yourself" she shows insecurity, but as it worked fine with my set, she responded
"yeah it happend a few months ago while I was in germany"
Now it was easy street for me, I made a simple geasture to my wing to join the convo, so here we were talking to 2 girls we just met like we've known them for ages, we brought them for a afterparty the same night, this routine is good if used properly.
SF