You can have multiple sub-summary parts based on different sorts. Each becomes visible only when it sorting-field is included in the sort order.
You can set items on a subsummary part to re-sort the records so that another level of subsummary parts is visible or not, giving the effect of a drill-down report or sub-category info. It's all done with the sorting orders used for each button object.
I'm not re-sorting the data. The report is based on the date. Today's section might have 10 records being summarized - easy to scan. Yesterday's might have 500 - much longer. I'd like to collapse the 500, keeping the sub-sum header for "yesterday" and the total at the bottom of the sub-sum - just have the option of hiding the details.
Yes, done with sorting.
Least detail, sort on Date
More detail, sort on Date and field for next level of sub-summary.
The data will not appear to change order as the top levels of sort ar the same. The sorting or not sorting on the secondary fields after Date determine which levels of detail are revealed. It really is done with sorting, but sorting on multiple or single fields, in your case with Date always as the first ro top-most sorting criteria
I don't think you can unroll a detail part for just one record, but you can get close functionally...
Do something like this attched file seem like it will work?