Dynamic range in formula

[torstensson]

Hi,

I've have problem getting a dynamic range of cells into a formula.
Been searching for a while but can't find an easy solution.

I've attached a sample file.

I have a huge amount of data with products, store and prices. I want to know what ranking in prices I have on average for all products. I'm currently using the RANK fomula. But since their is different competition on different products the range of cells needs to be determined somehow in the RANK formula.

Or maybe their is an easier soultion.

I'm using Excel 2010

BR