Show only direct descendants in product categories

Hi there !

Im using WP 3.8.1 and WC 2.1.5

I have this structure in my online shop:

Chairs (category)
 - Chair 1 (product)
 - Chair 2 (product)
 - Chair 3 (product)
 - For the Office (category)
   -- Office Chair 1
   -- Office Chair 2
   -- Office Chair 3
 - For Schools (category)
   -- School Chair 1
   -- School Chair 2

Having the option in the category “Show Subcategories and Products”, the url mychairstore.com/product-category/chairs lists all products and categories but I just want it to display only direct children of the Chairs category (no “grandchildren”).

So, is there a way to take Office Chair 1, Office Chair 2, … and School Chair 1, 2… off the list ?

Regards.

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