Hide Membership of a Mail-Enabled Group
By default, the members of a mail-enabled group are visible to Microsoft Outlook users in the group's Properties tab. However, you can hide the membership of a group using the Exchange Task Wizard.
Note The following is the only supported method for hiding the membership of a group.
To hide the membership of a group
Note After you hide the membership of a group, you cannot modify the group's security properties. When a group's membership is hidden, its access control list (ACL) stores entries in non-canonical order. Although this format allows Exchange 2000 servers to expand group membership for message delivery, it prevents any modifications to the group's security properties. The following message will appear if you open the group's properties and click the Security tab:
Windows can not edit the permissions on group name because they have been written in a nonstandard format by another application. To enable editing, you must use the application to restore the permissions to a standard format.
Related TopicsUnderstanding Group Management and Security