The Borders of the European Union From Micro and Macro Point of View

It is well known that one of the most important elements of the EU is the free factor flow. Firms as well as individuals use these possibilities and continue their activities abroad. To take only a simple, but very actual example: a lot of Hungarian physicians have moved to Norway, thus the "market" for Hungarian physicians is not bounded by Hungary's borders. Having this in mind, how should the territory of a region be determined if it is acceprad that markets play an immens role is this field. Is it right to say that the European Union as centrally established structure is avoiding the aggregation of its microun its, countries, regions, etc.? How should be interpreted from this point of view aggregate demand and supply, general equilibrium in Europe, or totally all over the world? Is this traditional and mainstream approach of economics true for continents or other "big" areas, and observable disequilibrium situations refer problems int he spatial structure of demand and supply?