First tell me, do you use the "Inherit parameters from category" option for the Children categories to inherit from the parent category the parameters?

If yes, you will have to transfer these parameters to another category and change the inherit accordingly.

Then, open the parent category and on "Category view options" set all items to 0.

By doing that your parent category page, like the one you have sent to your screenshot, will not show any items under the category blocks, like it does now.