I don't know of any way to customize the pie charts as you would like. Try running textual reports instead. Those will show subcategories indented from their parent categories and will be easier to read.
Quicken's charts are not very configurable. You may be able to get the results you want by exporting the report data to Excel and plotting it there.
Also rather than having main categories as broad as Personal, Business, and Rental, you might want to use Category Groups for that level. You can then easily select just one group at a time in the Spending by Category report for more detailed reporting and the pie chart will not show the group name. Category Groups also flow nicely into Quicken's Budgets.