The solution is probably simple, but I'm scratching my head on how to do this properly...
I have a shop where I want some of the top groups (let's say fruits, vegetables and nuts) to appear in the top navigation, i.e :
HOME - FRUITS - VEGETABLES - NUTS - ABOUT - CONTACT
THere are other top groups but they are not meant to be navigated.
When you click on FRUITS/VEGETABLES/NUTS, you get to a product catalog page where you can see the subgroups of the group you have selected (and not the other ones). For example, if I click on "fruits", I should go to mywebsite.com/fruits, and see in my left navigation the subgroups "apples", "pears" and "bananas" (and nothing else).
How can I do this ?