Seeking Numbers help. Pie chart & classifications

Not sure where to start with this one, so i thought I'd outline the problem and see if anyone has a solution.

Lets say I have a list of stocks,and each stock has attributes such as name, value, geography, risk etc

I might have

Stock Name Value Geography Risk Type
Stock A 50,000 Europe High
Stock B 25,000 Europe Medium
Stock C 75,000 USA Low
Stock D 80,000 Asia High

Is there a way to use Numbers to display various pie charts, eg not just stock names vs value, but also showing, for example, the breakdown, on a value basis, of high, medium and low risk stocks, and stocks in different geographies, without me needing to add it all up manually?

Or do I need a database to do this kind of operation?

TIA

Answering my own question, use table categories, sort of a mini-pivot table.
A very nice explanation here http://macmost.com/pivot-tables-in-iwork-09-numbers.html