Custom unstructured events

I have been trying to model an unstructured event for an ecommerce website which has a faceted search feature with many different variations:

  1. Search for “Electronics”
    – Phones
    – Home appliances
    – TVs

When I select any of the sections: I might end up having custom facets for each section like

  • OS
  • Memory Capacity
  • Brand/Make
  • Screen Size

Home Appliances - Refrigirator:

  • Brand/Make
  • Capacity
  • Door Type
  • Energy Rating

It has been difficult to model this kind of event with the unstructured event as the property field doesn’t allow nested structure and its difficult to set a structure as mentioned above. Also, with the additional complexity of selecting multiple parameters with in each facets.

Has anybody done anything like this before and have a better approach in solving this problem, any help appreciated.