Shoutbox

I think you missunderstood
The command I was talking about is one you receive
its like /ping command.
when you send it, you see "Ping? [request]" instead of actual command, and when the contact answers you see "Pong [05sec]" and the command sent by the contact.
This is exactly what I'm trying to do. When you send a command it should display something else in the window, yet, the contact to whom you send the command should receive the command and they also should see something else instead.