Per user configs with the Spamassassin plugin?

[Mark Farver]

Someone mentioned here a few days ago that there was a way to have SA do 
per user configs based on the To: field (or Rcpt to?).  I can't figure 
out how that would be done.  Anyone have any hints or pointers to where 
it is mentioned in the docs?

The closest thing I can find in the docs is spamd's -x and  
--virtual-config-dir options, but using those I just get configurations 
for one user: smtpd which is the user qpsmtpd is running as.

Thanks
Mark Farver