Gmail – Wildcard MX domain record and Google Apps

We needed to setup a distribution list where there were many aliases but they all were delivered to the same users. The best approach we found was creating a fake user account, setting up aliases on that account, forwarding the email to a real group, and using the group membership function to setup the distribution list. Works reasonably well, but having aliases for a group would be better.

Looks like you can also nest groups within groups. There is at least one help topic that recommends this approach. The above mentioned approach does give a few other features however, such as vacation responders and the ability to backup mailing list email using POP/IMAP.

To bounce messages addressed to non-existent recipients:

1. Log into the Google Apps control panel for your domain.

2. Click the Settings tab and then select Email in the left column.

3. • (Free edition) In the Catch-all address section, select the Discard radio button.
   • (Other editions) In the Email routing section, select the Discard radio button.

4 .Click Save changes.

Taken from this Google Help Article