Linux Mail Server Setup and Howto Guide

Hi all, I have used the setup listed to create a mail server with Centos 6. Everything works great in terms of setting up domains, sending/receiving, etc. I even added SSL certs to further protect my mail. I have one stumbling block as of right now that I am hoping I can have some insight with. To be clear my server is using postfix, dovecot, squirrel mail, mailscanner, clamav, and mysql to support multiple domains.

If I want to forward email that one account receives to several others how would that be possible with the configuration supplied within linuxmail.info? i.e. send mail to user1@domain.com I want that mail to be forwarded to user2@domain.com and user3@domain.com or even another domain for that matter

Is that something that needs to be done through postfix or squirrel mail. I know it would be easy if mysql was not involved. I would just have to map out the addresses in /etc/postfix/virtual but considering I am using mysql to maintain several domains i'm confused.  Thanks for any help.