Firefox n Sounds in seperate windows

Hi there, curious to know if there is a way to configure different windows so as to be able to switch sounds off in one browser window, but still keep them in another.
Eg.. I am host in a chatroom which alerts me with a BIIIING! when someone enters the chat. I am also in a different window playing a game with sounds on which doesnt have a seperate control within the game to remove the sounds. I want to be able to turn the sounds off in the game window while still being able to hear the dull thudding BIIING! noise of a person entering the chat room.
If there isnt a feature, im betting someone could write one...lol

Cheers folks

Alistair