permit smtp connections from specific country only

[Tom Kinghorn]

Good day list.

Without the use of policyd or postfwd, is it possible to
limit connections to your mail server from a specific country only?

I was thinking something like:

mynetworks = $config_directory/mynetworks
countryips = $config_directory/country_ips

smtpd_client_restrictions =
        check_client_access regexp:/etc/postfix/fqrdns.regexp,
        permit_mynetworks,
        permit_countryips,
        .........
        .........


Just wondering if its possible.

Thanks
Tom