I'm aware that I can change the layout of a specific category by creating a layout file with the name
123 is my category id.
How do I apply a layout change to the parent category (e.g. "Car Parts" with the id "123") and all sub-categories (and sub-sub and sub-sub-sub etc)?
What I'm attempting to do is load one block on a bulk of categories, and a different block on a bulk of different categories.