The following commands exist for you to talk to multiple people

newbie          fighter
kataan          cleric
mage            monk
rogue           hm

As well as chat lines for your guild.  The command to use each line is
the name of the line.  You may also send emotes over the chat lines
by appending "emote" onto the command name.  Example:

newbieemote smiles at everyone.

Would show to people:

<newbie> Descartes smiles at everyone.

To see who all is online, use the command "list".  Example: "list newbie".