Further 'research' on my behalf has led me to having a close look at maps of Norway. If I'm reading the maps correctly then there are numerous 'splitting rivers' as well as a few lakes with at least two outlets. I'm having a bit of trouble confirming some of the names with Google Maps and finding the right lake, but apparently one exists that has two rivers exiting it. One leads to the atlantic and the other to the sea near Sweden. Basically splits the country. I think the main thing required is lots of glacial action throughout the region/world's history.