Both of you "copied" postfix's "alias_maps" feature, which is what I can only assume has been a standard feature since the beginning of mail server time. Back when I was running our mail for my company (we've since switched to Google Apps), I had several entires in alias_maps that were like:
"managers@example.com" | "ryan@example.com,aaron@example.com,alyson@example.com,macy@example.com"
etc.
(Perhaps I'm misunderstanding this, but from your website it sounds like you're just describing a mailing list)