postfix mx relay and check for spam email on non local users

[Oberdan Albertoni]

Hi, I have a mail server configured with amavisd using SQL select clause 
to fetch per-recipient policy settings.
Now I have to do the same server also backup MX for a domain and I would 
like first to put in the postfix queue that receives email for that 
domain (if the mail server priority over the other is down) checks if 
that the email is a spam email.
I tried putting the domain in $local_domains_maps but if for example 
sending an email to the user test123 at domain.com and there is not the 
user test123 in the tables of the DB did not control spam.
How can I make him do a spam control without changing the DB tables ?
Greetings Oberdan Albertoni.


-- 
Oberdan Albertoni

-----------------------------------------------------------------------------------------------------------------------------------------------------------

DIGICOLOR.NET s.r.l. Via Ala Ponzone, 30 - 26100 CREMONA (CR) Tel. +39 (0372) 30669 - 1965101 - 1951509
Fax +39 (0372) 464840 E-mail info at digicolor.net - Website http://www.digicolor.net
C.F / P.IVA 01227520192 - R.E.A. CR n. 153382 - Capitale Sociale € 10.400 i.v.

Filiale di Codogno
Via Galilei, 17 – 26845 CODOGNO (LO) Tel. +39 (0377) 741006 – 431931 Fax +39 (0372) 464840
E-mail info.codogno at digicolor.net - Website http://www.digicolor.net

-----------------------------------------------------------------------------------------------------------------------------------------------------------

Ai sensi del D.lgs n.196 del 30.06.03 (Codice Privacy) si precisa che le informazioni contenute in questo messaggio sono riservate e ad uso esclusivo
del destinatario. Qualora il messaggio in parola Le fosse pervenuto per errore, La preghiamo di eliminarlo senza copiarlo e di non inoltrarlo a
terzi, dandocene gentilmente comunicazione. Grazie

This message, for the D.lgs n.196 / 30.06.03 (Privacy Code), may contain confidential and/or privileged information. If you are not the addressee or
authorized to receive this for the addressee, you must not use, copy, disclose or take any action based on this message or any information herein.
If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation.

-----------------------------------------------------------------------------------------------------------------------------------------------------------