[ale] Many domains, one Cyrus

[djinn]

I am looking for a way to set up cyrus (2.0.9) to deliver to mail boxes
that are unique within their domain but not necessarily across the
entire server.

For example, we have a client named Chris Primus, chris at client1.com.
We have another client, Christopher Secundus, chris at client2.com.

These are obviously not the same people, and their mail should go to
different mailboxes.  The obvious and oft-suggested method for this is
to create mailboxes named chris.client1 and chris.client2 and map,
either with aliases or LDAP, chris at client1.com->chris.client1.

This is fine and works well once you get it set up (I have).  However,
both Chris's have existing accounts with us, both Chris's pay us a lot
of money and both Chris's are not technically savvy and will get very
annoyed if I call them up and tell them that they have to change their
Outlook mail settings to log in as a new, harder to remember username to
check their mail.  I have read that Cyrus can handle this sort of
thing.  Can anyone who's faced a similar situation help me out?

TIA
jenn