Spam email -possible to block a small country?

Spam email -possible to block a small country?

The general spam filter Zoho uses has been very good, but in the last week a BUNCH of spam emails from the small country Palau which is the .pw extention, have been getting through.  I want to block the whole country.  Can this be done in Zoho?  I know it can in MS Outlook.

Thanks,
Paul