Solutions:
- Configure select box containing the category hierarchy under 'Countries'.
Octopoos has a plugin called 'Joomla Categories'. This field plugin generates a selectbox showing the hierarchy with a settable separator.
- If an article is tagged with i.e. 'Austria', 'Germany' and 'Suriname', it shall be found choosing 'Europe', 'Africa', 'Austria' or 'Germany'.
I made used the field plugin above in a FieldX. The stored data can be filtered in the search form.
- Search shall show articles within category 'Types', only.
The search just shows items of the type set in the search type.