Not sure on how to explain it but looking for a way or and extension to narrow down product lists. The site I am developing sells toners so would like a self populating list boxes from Categories ( e.g. Brands)-> Sub Categories - > Product models. E.g. First list box will be "Brother" then second list box will populate categories like, "Ink", "Colour Toner" etc., And then the third will populate based on second list box selection. Search will then search the products with the appropriate models.
For categories I am using Brand names, Sub categories are the machine types, and then the products wil be listed with their appropriate model compatibility into the model field.
Hope this helps but if an extension does something along these lines, would greatly be appreciated on how to setup.
