Hi Simon,
I'm not sure what your question is. In WP you can assign each post to multiple categories or sub-categories.
Lets say your post "Skiing in Alaska" is assigned to Category : Skiing and Destination : Alaska.
When a user is browsing by category, they will see all post is the main category and subs as well, including the post "Skking in Alaska". Same goes for Destination.
-gk- |