Quite a simple suggestion:
Basically you would type a command in the chat and it will show you a list of GM's that are currently in game. It can be useful if you need quick help with something. I know IRC exists but I find GMs that are in game would react faster to your situation then IRC would. Also it's much faster for the players.
I know you can also /sa the name of each and every single GM, but it's very time consuming and you might not have every single GM in your head.

So the command could be sometime simple like "/GM on" or something along the lines.
Thank you for reading, let me know your opinions, pros and cons etc...