U missd the point - Country is a key in both the tables - Home & Carmaker (see p.146 in the manual).
In adition - lets take the situation one step forward - now lets consider that i have a big table of countries, with many columns, such as flag image, and population, area in square meters, UN symbol, continent, and many more.
the Q is - how to load the table once but use its data twice, without affecting eac other.
I believe it has to do with some design pattern such as using QVD or whatever.
See page 146 in the manual and add one more table of countries.
For my Q:
I used to work few yesrs with microsoft SSAS and it was posible to load the countries table once and use its data as many times as you like, with the option to select CANDA as the Carmaker country and USA as the BuyerHome country.