Yes, you can. Just follow these steps:
- Create a new Google Group with no members.
- Switch that group to a remote archive. To do so, click the Group settings link, then click Advanced. On this page, select the option 'This group is hosted on another mailing list host.'
- Carefully review the information on the Learn More page. (A remote archive works a bit differently than a regular Google Group; you'll still be able to search the archive and post messages to your mailing list via the online form in the group, but you won't be able to post to the Google Group via email because all of the messages will be coming from your mailing list. Also, your subscription choices for the group will be limited to No Email, Digest, and Abridged.)
- Copy the special email address listed on the page; you'll need to use this address to subscribe the remote archive to your existing mailing list.
- Once you've read all the information on the Manage Remote Archive page, select the option 'Yes, this group is hosted on another mailing list host' and enter your mailing list's address.
- Click the Save Changes button, and you're ready to go.
Keep in mind that any mailing list that disallows @googlegroups.com email addresses can not be remotely backed up using this feature (for example, Yahoo Groups).
We don't currently have a way to transfer your mailing list's older messages to the archive. Only new messages to the list will be stored in the Google Group after you subscribe the special email address.