Combine databases of different countries

As we live in Denmark close to be border of Germany we often buy food in Germany. Unfortunately scanning the food from Germany showed not to be recognised. I then got the idea to swop my reference to Germany, which then worked. I then again changed back to the danish reference to continue.
The idea is to have the possibility to add more than one reference database, which will make it easier. I imagine that many others might have same wish living close to other countries.