Hello Hogi,
As far as I know, there is no grouping option for the recent files list.
These tools can help you to find your recent files more easily :
- the search bar to look for a recent file from the list
- the tools (top right of the Recent Files part) to sort by name or Filter by type the files in the list.
You can also suppress the files you do not need from the Recent Files list (right click > Remove from the list).
I hope this helps.
Elodie