I suppose you could accompany your built game with a java app that is loaded from the web page, then the java app would start your game... but what's the point? FPSC can't interact with java, the best it could do is send in a command line argument saying that it wants to load it up as a multiplayer game, and we all know that that's not how FPSC works... it's either MP or SP right now, not both.
On top of that, MP games in FPSC don't utilize dedicated user made hosted servers. You would have to Mod it (severely) in order to do that.
The one and only,
Whosoever says, "Don't sweat the small stuff," is obviously not a programmer.