Siberia isn't a country. It's not like Wales or Scotland who, while not being an independent country, have certain distinctions from other parts of the United Kingdom of Great Britain and Northern Ireland (linguistic, historical ones, maybe even administrative (don't know about the administrative distinctions, though)). Siberia isn't a unit in any sense (neither linguistic nor administrative), except for the territorial one (indeed, some territory of Russia, after that the USSR, after that Russia (Russian Federation) once again is called "Siberia").

 

It's like to write in the "Country" column "Bavaria" for the group from Munich or "Schwarzwald" for the group from Stuttgart (instead of "Germany").

 

It should be written "Russia" (if they are indeed two Siberians).