Raise Event for All Users on a Page at a given time

Hello All,
I have a simple chatroom system written in ASP.NET 2.0. What I am trying to do is to raise an event for ALL users on the chat page, using which a WAV sound clip is played, every time a new user enters the chatroom.
I already know how to play the sound clip, but what's the easiest way to raise the event for all users? Would static event do the trick?
 
Thanks,
Pete
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