[Server Admin] Associate your server with a steam group

You need to be the administrator or an officer of the Steam group.

1. Connect to Steam and go to your group page, then click on the "Edit group profile" link

2. Edit cluster.ini file and add the following lines in the [steam] section :

[steam]
steam_group_id = YourGroupID
steam_group_admins = true
steam_group_only = true

Setting steam_group_admins to true will automatically make administrators (but not moderators) in your steam group administrators on your servers as well.

Setting steam_group_only to true will only allow members of the specified group to connect to your server. If you set it to false, your server will be open to everyone (unless you specify a password) but it will appear in the top of the server list for members of the group.