Player Groups are also called guilds. Players in a guild have an own global chat only members in the same guild can use, just like the chat tab for parties. The currently used guild system includes the Guild (Bot), meaning all actions, like inviting new members, are directed to him. When your guild chat tab is missing it's most likely because Guild (Bot) is offline.
Note: Below you can find short desciptions of some guilds. Please, try not to be chaotic while editing this page. Try to preserve the format, and do not create derived articles for your guilds. Here we have enough space for your guilds.