Pivot Grids Help - Change Amount via Prompt?

Hello,

I'm trying to provide a solution to a question an end user posed to us. We are developing some Pivot Grid analytics related to purchasing. For example, looking to capture spend by supplier. We have thousands of suppliers, so the users want a way to be prompted for a dollar threshold for which suppliers are returned in the Pivot Grid (i.e. display only suppliers with $1M+ in spend, $3M+, $5M+, etc.)--However each users wants to filter the data.

It's simple enough in a query to just have the SUM(AMOUNT) > [prompt], but is there a way to do something similar in a Pivot Grid? I quickly discovered prompts are not allowed for Values on Pivot Grids.