The Group Manager allows you can create groups with a unique name to group users. Assign users to these groups by using the update user function. Currently, this function can be used for administrative purposes e.g. listing/massmailing all users of one group.
The @Mail the group system will also have an important role in spam filtering and general permissions. In the @Mail SQL database, user account records (Users Table) contain a field called 'Ugroup' which define what group they are included in.