I am trying to create a page that is a list of categories that contain posts that are also in another category.
For example, I have cat1, cat2, cat3, cat4, cat5, catY
I want to create a page that lists all of the categories (cat1 ... cat5) that have POSTS that are also in catY, without displaying catY in the list.
I assume it would be easy enough to skip the catY output with a simple if/else test inside of the loop.
What I am trying to figure out however, is how to set up the loop, as this seems to be beyond the "wp_list_categories" type of setup.
Any thoughts or suggestions? I would think that someone has already tackled this scenario.
P.S. I do not want to use a plug-in to do this. I would prefer to create one (or more) custom page templates).