[exim] Excluding hosts from rdns checks

Good morning, I'm trying to set up the rdns checking to my server, but
due to many providers not using reverse dns registers for they ip's
it's no trivial.
At this point i built a list of all the hosts for the country using
the database here. http://phpweby.com/software/ip2country
I would like to this:
.- If the sending host is within the country list, no rdns checking
should be done.
.- If the sendign host is out of the list, usual checks should be applied.

This is what I got so far:

  .ifdef CHECK_RCPT_REVERSE_DNS
  warn
    message = Country hosts doesn't require rdns
    hosts = ${if exists{CONFDIR/hosts_in_country}\
                 {CONFDIR/hosts_in_country}\
                 {}}
  defer
    message = X-Host-Lookup-Failed: Reverse DNS lookup failed for
$sender_host_address (${if
eq{$host_lookup_failed}{1}{failed}{deferred}})
     condition = ${if and{{def:sender_host_address}{!def:sender_host_name}}\
                      {yes}{no}}
  .endif

The problem is that currently the two tests are being done, and I
would like the second one to be skipped if the first is positive.
Which would be the way to accomplish that?

Regards