subnav/product filter widget based on choosen product category

Hey,

Im having an idea how i want my wordpress page to be setup, But im at a loss on how to achive this.

Right now I have my main product categories as my main navigation.
ie Ford, BMW, Mercedes, Toyota.

Im using the Woocommerce productcategories as my filtering and the best i can go with this is that if someone visit the “Ford” category my menu looks something like this.

Ford
Ford Subcat1
Ford Subcat2
Ford Subcat3
BMW
Mercedes
Toyota

But i would rather want my filtering to be based on only the “Ford” subcategories so the filter menu would only be something like this:

Ford Subcat1
Ford Subcat2
Ford Subcat3

And if they wanted to visit any of the other brands they would have to go through the main navigations.

Is this possible within woocommerce, or another plugin or widget, or does this have to be coded? (im not that familiar with php coding except trail and error)

This is a good example of a woocommerce site that has this feature:http://showtimecaraudio.net/
http://wordpress.org/plugins/woocommerce/