I need help to understand how I can hide the contacts of a certain nation to a group of employees, I tried to put a record rule but the situation does not change.

This is the domain filter of the Record rule: [('country_id','=','233')]  
It has as object "res.partner" and the group name (the rule isn't global) is the one of the group of users that can access only to the contacts with country_id:233.

The problem is that when i log in with a user inside that group I still see all the contacts and not only the ones with country_id = 233