New SMTPD Policy

Hallo,
	I just installed a new Kolab server V 2.3.4 for production environment. 
I put it in production next weekend.

The server will be multi domain and I'm trying to implement a Policy 
different from domain to domain.

For example I have customers from a domain that need to have all mail 
coming from Russia to be considered valid ones.
Customers of others domains wants a filter to block spam from Russia.

Some other customers ask that every recipient in mail they send will go 
in a permanent white list. So I need a different white list for every 
mail defined in kolab for that domain.

The actual filters and policy in Postfix don't have a solution, for what 
I know.
Postfix check_client_access, check_helo_access, check_sender_access can 
help but in a site general mode, not on a domain or single email mode.
I have a look at policyd, but it seems to have the same limits.
I don't know if kolabpolicy could help.

I looked around and found nothing that could help me.
So I think to write a new policy that use a file or a db with 4 
information to correlate:
Client IP
Helo/Ehlo
Sender
Recipient

My idea is to check not only one field at a time as can do actual filter 
in postfix, but to aggregate two or more during check.

In postfix source code there is a simple example of greylist policy.

I think to modify that code to implement a new policy, with a higher 
granularity.

Do you know a better solution, or something already done?
Any idea will be appreciate.

P.S.: I apologize for my poor English.

-- 
ing. Andrea Gelpi
***************************************************
La Terra non la abbiamo ereditata dai nostri avi,
ma la abbiamo presa in prestito dai nostri bambini.
***************************************************
We do not inherit the Earth from our parents,
but borrow it from our children.
***************************************************