Tell
From MUME
The tell command can be used to send a message to another player, regardless of where they're located. Sleeping players cannot hear tells.
'tell group' lets you send a message to all the players (but not mobiles) in your group. Note the messages are all sent after a delay equal to the time that would take sending individual messages.
Examples
> tell CryHavoc You're dead meat - sucker! [not advised] > tell group Let's meet at Bree