Barbara + Dinah + Zatanna
Zatanna smiled at a passing waiter, taking a skewer of chicken and a napkin before moving along. She was thinking about taking a breath of fresh air when she spotted a familiar red head in an almost equally familiar chair. Oh, sweet. This was going to be fun! (Sure, she didn't have a secret identity, but she knew how to play the game. Well, Bruce would probably blanch at hearing her call it a game but regardless. She knew the deal.)
Swooping in once Dinah excused herself (she recognized the blonde, as well, but figured she'd let her set the pace there, since neither of them wore masks), Zatanna was grinning widely-- perhaps too widely but it couldn't be helped. This was going to be hilarious! "Hi, there. You're Commissioner Gordon's daughter, right? Barbara, isn't it? I've heard so much about you from the Commissioner and Bruce. You're a librarian, right?"
She made a show of looking abashed. "Oh, where are my manners? I'm Zatanna-- Zatanna Zatara. Just another member of the help this evening but on break at the moment." Blessedly. She was definitely going to need another glass of water before she went back on.