I have a multimedia keyboard that allows me to easily mute the sound (Ubuntu 12.04). It would be nice to "link" this to also turn off libnotify messages that pop-up in the top right corner (i.e. Pidgin messages).

So when Ubuntu is muted, no libnotify messages would pop up. When not muted, messages show as normal.

Is this possible with a script of some kind or would it require changing source code?