Portfolio – link from category to sub-category and then link to items?

Hi,

I have a question: I use the Portfolio element. Is it not possible to insert a protfolio grid which are linking to a sub category instead of a item?

E.g. I have a product category called “Display Systems” In this category there a 3 sub-categories: “wall displays” – “desk displays” and “Floor display” and under each of the sub categories there are products.

So what I would like is that when you click on “Display systems” it opnes the 3 sub-categories and then if you click on “Wall displays” it shows all the items put in this category.