Not sure if you can do this directly in SM using their rules - I don't know if the rules now allow continuing to the next rule after a rule is executed so...
You might try Ultimate Spool Manager from mightyblue.com. I think it's still supported with the latest versions of SM. You can put wildcards in as addresses, and it should be able to relay everything coming or going, while still delivering incoming/outgoing emails to their originally-intended recipient.
What I do for archiving doesn't require an appliance: I just have SM set to archive everything, coming and going, and then do good backups. This way we simply have EVERYTHING, and multiple copies of it. All emails are compressed in the archive, so it doesn't take much disk space. YMMV depending on total email volume, of course.