The phrase "country sets" could be substituted with a number of synonyms depending on the intended context. In terms of geography, it could be replaced with "nations" or "states." In the context of a cultural event or exhibition, "nationalities" or "ethnic groups" could be used. For sports tournaments or competitions, "teams" or "representatives" might be more suitable. In economics or politics, "regions" or "blocs" might be more appropriate. Overall, the choice of synonym depends on the specific context and the intended meaning.