In the "Query" tool, I can group by pretty much any combination of account, tag, and category, OR I can group by payee or by recurring ... but there's no way to group by category, and within those categories show payees. I would like to be able to group by "Category/Payee".
(My specific use-case is that most of my regular charitable giving goes under one category, but each recipient gets their own line-item in my budget spreadsheet, and when I do my year-to-date budget check I want to be able to see which of those I've done for each month.)