Drill up & Drill Down + hide Rows

Hi,

I am having a Report where I need to show Sales by Category, Sub Category & Product.

Drill Down/Drill up Capabilities need to be provided to the business.

Now business does not want to see the Products with where sales are less than 10... And this should not reflect on Sub Totals and Totals..

I am planning to hide the products with sales less than 10; but the drill down and drill up buttons are not working properly..

please help!

Regards

Shiv