How postfix

Hi,

I have a postfix with different domains.
I need to route messages using different ways for each domain/mailbox

I have mydomain1.com, name of users are in joomla mysql database, the
email to user@mydomain1.com have to be redirected to email used for
registeration, extracting the alias with virtual-alias

But postmaster, root ... are not in mysql database for mydomain1.com

mydomain2.org, user's mailboxes are in dbmmail database.

So, I really need to know how to configure postfix for that.

Best regrads, sorry for my obsfuscating language ...

Bertrand