Only administrators can add, modify and delete Mailing Lists. Normally the administrative account is the "postmaster" account. Since the postmaster is responsible for managing all accounts in the domain, it cannot be used as a mailing list name, however you can include the postmaster on any mailing lists you create.

Creating Mailing Lists
You can create mailing lists by clicking on the New Mail List button in the Mailing List screen, or by using the fast link on the main menu.

To create the mailing list, enter the name of the mailing list and the email address of the list owner. To save the new mailing list, click on the Add button on the Add Mailing List screen.

Deleting Mailing Lists
To delete a mailing list, you click on the delete button in the Mailing Lists screen. If a mailing list is deleted, only the mailing list name is deleted. The subscriber accounts will stay on their servers and all email previously sent to them through the mailing list will still be there.

Mailing List Subscribers
To view or modify the subscribers on a mailing list, click on the Show Subscribers button in the Mailing Lists screen.

Example
  Mailing List Name: mylist
  List Owner: me@mydomain.com
  Subscribers:
    someone@mydomain.com
    another@mydomain.com
    user@otherdomain.com

In this example you would already have the account "me@mydomain.com" and this account will own the list "mylist".

Any mail sent to the acccount "mylist" will automatically be forwarded to all subscribers, in this case "someone" and "another" at your domain, and also to "user" at some other domain.