It would be useful to be able to create subgroups within account groups on the Reports page, so accounts can be organized hierarchically rather than all appearing at the same level. For example: a Banking group could contain Checking, Savings, and CD subgroups; an Investments group could contain Retirement and Active Trading subgroups. This would make it easier to view immediate vs short-term vs long-term cash without everything being flattened into a single list.