I have at least a user that have a old problem with duplicated mails, when it receives from a distribution group.

For example, when a **User 1** from the inside domain, send a mail to a Distribution **Group A** of the same domain, where a **User 2** is, this last user will receive two mails.

The first one is the original, where it cames as expected. The second one, is the original one, forwarded with the same heather, but with the list of the distribution group:

[![enter image description here](https://i.stack.imgur.com/JefmO.png)](https://i.stack.imgur.com/JefmO.png)

Note: this User 2 is classified as an administrator of this server.

Server Specs:

* Windows SBS 2008
* Exchange 2007

UPDATE 1:

Windows SBS 2008 is installed in my smart host, who is connected with my remote mail server, where i can config through cpanel. Forwarding at cpanel, means forward to another email account and it saves a copy at original destination. 

In my remote mail server i have those forwardings:

User 0 -> **Group A**

**User 1** -> **Group A**

User 3 -> **Group A**

User 4 -> **User 2**

User 5 -> **User 2**

And in my smart host:

**Group A** -> **User 2**, User n, ...