I am setting up a form for a customer. The form is used to enter articles (products). Each article has a supplier, and each supplier has one or more article (product) categories. A simplified example of the supplier to category structure follows:
Both the categories and the suppliers are individual custom post types. After considering using the categories built in to the system it was decided this would quickly become overwhelming to the user, as currently there are over 40 different categories, and each supplier has only 1 to 5. The categories overlap as shown above, more than one supplier can have a specific category assigned to them.
In the article input form, I want the user to be able to select a supplier, and the form filters the category list according to which categories are associated with the supplier.
I have the supplier selection set up as a post object, works as expected.
How do I program ACF to filter the Category list for the article based on which categories are assigned to the select supplier?