Filter by Top Level Keywords?

Is it possible to filter and find all the images that have a top-level keyword - let me explain

If I have a keyword hierarchy along the lines of

UNITED KINGDOM
       ENGLAND
             Yorkshire
                   Leeds
                   York
              Cornwall
              Dorset

      WALES
             Powys

       SCOTLAND
              Ayrshire

How can filter those images tagged ENGLAND, but are not in any of the sub categories?

What if I wanted those tagged Yorkshire – but not in any of the sub categories ?