Employee warning system

This is somewhat security related. My organization wants to be able to notify logged-in users of a safety issue (fire, intruder, etc.). The text messaging is a piece of cake (this is a Novell based Network). What they also want is an audible warning to sound at the user station to get the users attention.

Is there a way to impliment this without a bunch of custom programming? Is there a commercial or shareware product that already exists?

I’m open to suggestions.

Dick