I am guessing you have inbound numbers (DID) from these countries for people to ring in.
You can address this in many ways.
- Using a single inbound route dialplan with "groups" matching the country code as condition. You probably need to set break='never' for the condition to progress through the groups.
 
- Using different dialplan blocks for each country code.
 
- Writing your own Lua script and directing incoming calls to the script.
 
I would go with the first option to keep everything in one place.