The idea is pretty interesting and I’ve not seen such a thing before in the contractor directory industry. Even Google maps doesnt do this.
I don’t know the technical term for it, but i’ll call it a 2-tier listing structure. The 1st tier are the list of contractors/businesses. The 2nd tier will be a listing for each service job that the contractor can perform.
It’s very similar to you selecting a restaurant and browsing through its menu items. The only difference here is the restaurant is actually a contractor, and the menu items are the services.
This is going to add a lot more complexity to the site. It’ll also add more work for contractors since it’ll (optionally) ask them to fill out a new form for each service that they might specialize in.
If I end up adding this feature, I wonder if it’ll even work.