Oh. Um. Not specifically, but if you would like to specify something now that's fine, or 'Za can just do something that seems like it could be a signal, say "that's the signal", and we'll say that's what it was all along.
I'm assuming that 'Za has her comm link. Is there any reason to think the signal would be blocked from inside Gulgo's hideout? She would test at some point, just to be sure.
If it works, 3 beeps (short-long-short) on a specific channel/frequency should do the trick.
As to your IC question, the pimp and women are kind of in a "museum tour group" formation. The pimp is at the head of the group, facing them, with his back to the blast doors. Which means I'll take your action as getting over with the counted girls.