Whipped (2000)

One day at the diner, Brad, Jonathan, Zeke and Eric see Mia hanging out and fooling around with these foreign guys; she says that she'll call them, she leaves the diner with the foreign guys and that's the last time that Brad, Jonathan, Zeke and Eric see Mia. They go back to their single life (except Eric) and some time later, the habit of hanging out at the diner, dies out. Also, it turns out that Mia is a scammer just like them and she also hangs out with her friends at a restaurant to talk about dating and sex (only that she's the opposite: a woman and she dates guys and then leaves them). That day, when Brad and company where making their moves on the three women sitting on the bench, Mia was sitting in another bench nearby; right there and then, while watching the three of them hitting on the three women, she decided that the three of them are the perfect candidates/targets and that she would date them at the same time.

Erik