I was wondering if its possible to have a diffrent _horses file for every country in the game. So you have real horses names in there right country.

The four playable countries each have their own horses file. At the moment, they are all identical, but they can be amended separately. However, for example, if you play a UK game that includes horses from other coutries, you wouldn't be able to specify which horses' names are used for the horses from other countries, as the names are used randomly.