Blocking international IPs to One Client in Multi-Tenant app Question Fortigate

Like the title says. Our prod app is behind the same IPv4. Using Fortigates. Customers get to their app like prod.us.com/<customer>. We promised to block all international IPs for one client. It's looking like maybe we can filter traffic by the destination URL, and apply this policy to only traffic targeting that URL?

Just looking for some insight and ideas!

Thanks :)