Active Directory security groups can also be mail-enabled, this allows them to operate as both a security group and distribution list. This will result in a single list of members to be administered through Active Directory.
Please note, these instructions are for an existing security group.
To mail enable a security group-
Start the Exchange Management Console.
In the console tree, expand Recipient Configuration, and then click Distribution Group.
In the action pane, click New Distribution Group. The New Distribution Group wizard appears.
On the Introduction page, click Existing Group, and then click Browse.
In Select Group dialog box, select the group that you want mail-enable, and then click OK.
On the Group Information page, complete the following fields:
- Display name By default, the display name is the same as the group name. You can modify the name in this field.
- Alias By default, the alias is the same as the group name. You can modify the name in this field.
On the New Distribution Group page, review the Configuration Summary. To make any configuration changes, click Back. To create the new distribution group, click New.
On the Completion page, the Summary states whether the distribution group was successfully created. The summary also displays the Exchange Management Shell command that was used to create the distribution group.
Alternatively you can use the Exchange Management Shell-
Enable-DistributionGroup -Identity "Security Group Name"