New structure of sales territories

Hi together,

I want to build a new structure concerning the use of areas, countries, regions and federal states.
For example: We have five areas. One of them are the USA. The area USA is divided into four sales regions with several federal states. Europe has a similar fragmentation - including Germany with its 16 federal states. Unfortunately the fragmentation for the sales persons in Germany is sometimes based on potalcodes of the cities.
This is the basic situation.
What would be your solution?

My favorite at the would be:

New entity : Country
Fields:
Name:Text
Area:OptionSet(Global)
Region:OptionSet(Global)
Countrycode:Text
Continent:OptionSet(Global)
DialingCode:Text
State:OptionSet(Global)

I'm not sure if this would be the best solution. Would it be better to create new entities for the States? Maybe two - USA states and German states? And what should I do with the postalcode partioning?

I would appreciate your advice and ideas.

Best regards
Mick