Sorting Grouped Records by Last Opened

Sorting Grouped Records by Last Opened

So, I have a form. For simplicity, lets say that this form only has a job_name field, a room_name field, and a order_number field. (the order_number field is to input a number for sorting purposes)

On the report, I have it set to group by job_name, and to sort the records within the groups by the order_number field.

It sorts the groups alphabetically by default.

I would like it to sort the groups by last opened. So for example, when I edit a room on a job that is at the bottom of the report, the rooms on that job would now appear at the top of the report.

What is the best way to accomplish this?