Ray,
I'm also testing this and I can't get it to work. Using SME 6 and the mailblock contrib as well.
My 90aliases:
info@domainXX.com:john
info@domainYY.com:jfranco
Both users john and jfranco are existing users on the server.
What happens when I send an email to info@anyofthedomains.com is a reply from the server
<info@domainXX.com>: host domainXX.com[200.174.XXX.XXX] said: 553 Sorry, that is an
invalid e-mail address (in reply to RCPT TO command)