I use CSF (ConfigServer Firewall), and it has an option to blacklist OR whitelist IPs by country. I use this to blacklist every country except for the US.

But now I have one hosting client that needs to accept international customers.

I don't want to disable this server-wide because then all clients will get a lot more spam and scam emails.

My immediate thought is to find something that I can apply to each domain to whitelist / blacklist IPs by country, then I could manually apply it to every client; a bit of work, yes, but then everyone has the ability to make their own choice. But I don't know of such a program.

Any suggestions?