Ouch. It's been so long since I've done that much in depth I'd have to teach myself.
I just looked at our gag code.
Using our gag idea is actually better than what I thought my idea was.
Though you could (and probably should) use those hooks on client side to then start updating a GUI/HUD and counting, once the counter reached 'limit', use the basic server side hook to flag PlayerCanHearPlayersVoice as 'NO' like we do in gag.
SetNWBool sets the switch on server and client.