This filter is used for group authentication. It specifies what group or
groups that this MM belongs to. If left blank, group authentication is
disabled. Otherwise, group authentication will be performed against the
filter. The filter can be a specific group name (eg. IMMWest), a wildcard (*)
which matches everything, or a wildcard with a prefix (eg. XCC*). The default
filter is XCC*.
After user authentication, group authentication will take place, whereby an
attempt will be made to match the group or groups (that the user belongs to)
to the group filter defined here. If there is no match, the user will not pass
authentication and will be blocked. If there is a match, the login permissions
for the user will be retrieved from the matched group(s), unless the user
already has login permissions assigned directly from the user record retrieved
from the LDAP server.