[Dovecot] Predicament

I have a little problem on my hands. I followed the following how to and made plenty of changes.

http://www.howtoforge.com/postfix_mysql_dovecot_dspam_clamav_postgrey_rbl_de bian_etch

However my basic setup is this:

Mail comes in via Postfix incoming mail server only. Sends it to a DSPAM machine who checks the mail for spam and the uses Dovecot to deliver the email.

My problem is this:

I have users setup with forwards in my MySQL database. So dovecot tries to deliver mail (such as to my blackberry) and it fails. What is the proper way for me to forward this mail outside of the local mailbox?

Should I use .forward files in the mailboxes themselves instead?

Thanks,

Fred