[exim] Virtual aliases configuration

Hi everyone,

I wonder how can be an ACL configured to

1. Lookup for the recipient address for certain domains
2. Check if the rcpt address exists in the valias file
3. If these 2 above are true - reject forwarded message

Shortly, something like this:

1. Client configures forwarders through the control panel

The valias file looks like this one:
PATH to it:
/etc/valiases/mydomain.com

content of /etc/valiases/mydomain.com
========================
test@???: techsupport@???
*: :fail: No Such User Here
========================

So the router check for the entries in valiases files and handles the
forwarding:
ROUTER:
=======================
virtual_aliases_nostar:
driver = redirect
allow_defer
allow_fail
data = ${if
exists{/etc/valiases/$domain}{${lookup{$local_part@$domain}lsearch{/etc/valiases/$domain}}}}
file_transport = address_file
group = mail
pipe_transport = virtual_address_pipe
retry_use_local_part
domains = lsearch;/etc/localdomains
unseen
======================

=====================================

I want to setup an ACL which

1. Checks recipient emails address, for example - *@aol.com
2. Checks if such entry exists in /etc/valiases/$domain (in the right
part after ": ")
3. Blocks outgoing emails if the message is forwarded to aol.com


Any suggestions are truly appreciated
Eugene