I won't get into the details unless somebody wants me to, but I use a system in which the nationalities of players who are already in my division determines where I'm allowed to scout. In the Turkish
Prem there are oodles of Brazilians, therefore you can scout Brazil. I re-research it by clicking on squad lists at the end of each transfer window.
This was inspired by one of the flaws in the old SWYCT system, which was that if you were in the Conference you tended to be the only team in it that didn't have Scandinavians. Is that "realistic" as in real life? I don't know. But the world you're playing in is the world in your save game, and it's not unreasonable to compete under the facts of life in that world.