We have a 3 tiered item class setup with each grouping getting more specific.  A real example is:
Level 1: Draft Beer equipment
Under that parent we have
Level 2: 01-Air Tanks, 02-Regulators, 03-Couplers, etc...
Under each of these levels we have our most detailed (using Air Tanks as my example)
Level 3: 01-CO2 Tanks, 02-Nitrogen Tanks

I would like to be able to have search filters where I can select any level and see all the products that fall under that hierarchy. 

So if I select a Level 1 item class I see all the products that fall under it.  If I select the Draft Beer parent I would see all the Air Tanks, Regulators, Couplers, etc.