Hosting multiple online players

Okay, here's the situation:

I'm having some friends over to have a sort of pseudo-LAN party, and the number of people has quickly swelled to probably around 15 people. My local infrastructure should be fine (a couple switches, multiple WiFi routers setup on different frequencies, etc.), but my question is how well my internet connection will handle having that many people playing. I can obviously do a LAN-only game, but I have some out of state friends who'd like to play with us, so it would be optimal if we could play online. We won't be hosting a server or anything.

Does anyone know how well my home internet connection will be able to handle that many players? I have cable, we typically get anywhere from 20 to 30 mbps down, and probably 7 to 10 mbps up. We're probably going to be primarily playing Team Fortress 2, if that matters.