local configuration for redirection

[Ivan Longhi <iv...@rcm.inet.it>]

I'm running SA version 3.1.7 on Perl version 5.8.8 on a Debian box trough
exim4/sa-exim.

I handle mail for different virtual domain.
I have no local users on the server, so I use just redirections
as I found in the net I handle redirection for single virtual domain with
this router for exim:
remote_local:
  driver = redirect
  data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
so I can write in /etc/aliases:
foo@mydom.org: foo@somewhereelse.com
bar@mydom.net: bar@everywhere.com

everything works...

my problem is: if a virtual user (ex. foo@mydom.org) ask to me to
personalize a spamassassin rule, how can I do it without using a system
wide personalization in /etc/spamassassin/local.cf as I can't use
$HOME/.spamassassin/user_prefs?

thanks

ivan