Linking Category to a taxonimies

Hello,

I have an issue using taxonomies on the “add listing” page

My aim is to have 3 layers of categories for the listing so a buyer can refine there search and have the seller place the listing in the correct category.

What I would like to do is link the “category” field to the Sub-sector taxonomy (as per the image attached) and sub-sector taxonomy to sub-category taxonomy. But it seems you can’t link the “Category” field to anything.

I have currently 3 taxonomies. One is replacing the “category” field but this type of setup isn’t the best because it still shows the now redundant “Category” field on the “add listing” page and the “My Subscriptions” no longer works because listings are not going into the categories this uses.

I’d like to be able to link the “category” field to a taxonomy as it would fix this problem without causing other issues But I don’t know how or even if this could be accomplished? or is there a better way to do this?

Does anyone know?

thank you.