Announcement and Discussion Lists after Migration?

Can these tools still function after an MX Record is created for a new mail host? I've migrated some email users over to Zimbra because they hated Squirrelmail, but I personally think Mailman is superior to Zimbra's Distribution List functionality at this stage.

After some analysis, I believe I might approach this by:

1. Add a new MX record for lists.mydomain.com to point to the existing A record for lists.mydomain.com.
2. Create a DL in the new mail environment that will have one recipient which is the name of the list @lists.mydomain.com.

This should cause the new mail server to forward any mail sent to
my @lists.mydomain.com to the mailman server where it will be broadcast.

The only trouble is, the web panel, wiki and this message board do not appear to offer any details as to how to proceed along this path.

Anyone have a suggestion? I'll create a support ticket and will report back here.

Alas, the web panel was taken down just as I clicked Submit on my support ticket, and my email to support@dreamhost.com was rejected. The autoreply pointed me back to the web panel!

Sigh...