In Delegated Administrator, a group is an entry in the LDAP directory that comprises a list of users. Characteristics of the group are not passed on to the users who are members of the group. For example, when you assign a service package to a group, the service package attributes are not inherited by the members of the group. The user entries in the directory are not subordinate to (do not “belong” to) the group entry.
When a mail service package is assigned to a group, the group becomes a mailing list, which is used by Messaging Server.
When calendar service is assigned to a group, the members of the group share group invitations and other calendar information managed by Calendar Server.
A mail group does not have its own mailbox; a message sent to the group address is delivered to the mailboxes of the individual members of the group.
However, a calendar group does have its own calendar; an invitation sent to the group is displayed on the group calendar and on the calendars of the individual members of the group.