[exim] Source IP based relay policies

Hi all,

I am setting up an outbound MTA. I need some help with setting up the relaying.

I have 2 classes of clients (base on IP addresses) connecting to this MTA. Class A is allowed relaying to any destination domain. Class B hosts can send only to domains abc.com and xyz.com. Any other clients are not allowed to relay at all.

SO how do I setup a ruleset such as:

 If ($client_ip_in_classA) then relay = allowed;
 else if ($client_ip_in_classB) \
      && (dest_domain == abc.com|xyz.com) \
      then relay = allowed ;
 else relay = not_allowed.

Thanks in advance,
ak