For the t-code OVE1, Only the authorization for transaction code is available.
You can't restrict as per country.
You can see it at yourself.
Go to SU24, give the t-code , then execute.
For you additional information
The information is stored in table T604.
You can contact with your abap team.
I hope they can restrict with this field T604-LAND1 for particular user..
They can restrict this via coding.