You might be able to do this by exporting the report to Excel, but that's the only way I can think of doing this. As far as I know, there is not currently a way to do this withing report writer or within the web interface. Hope this helped.
Will this need a FR? Management here seems to love pretty pie graphs and the less excel work I have to do and the more that can be auto generated will make my life a little easier :)
