So I have a PowerPivot Table that has tremendous amount of data. I have aggregated it in columns by customer along the left of the pivot table and my data housed in the columns to the right. Is there a way to dynamically group the customers into two groups so I can subtotal each grouping? I would like the grouping to be as follows: Top10%, and Bottom90%. I would like to subtotal each group for all of my columns of data. I am familiar with grouping in a pivot table but not DYNAMIC grouping that will update as I include more data from time to time.

I am not against adding some logic/columns into the base data in PowerPivot but I am just trying to think of a way to make this function.

Any help will be greatly appreciated.