How can I create a Cascade within a Cascade in SharePoint Online (modern or classic)?

Question

So my customer has these two lists (one classic and one modern) in which they'd like me to create a cascade within another cascade. Here's a snapshot of one of the lists:

As you can see, they tried "manually" indenting the second entry with dashes because the second document is related (based on the Title and Name columns) to the first entry. This list already cascades based on the "Directive Series" column. In this example, I'd like the first entry to cascade (drop-down?) and contain the second entry based on the Name column. SD100-HB1 should fall under SD100 based on its "SD100" prefix.

There are a bunch of these in this list, but I need a jumping off point. It was suggested to me by them to use JSON, but I've never used JSON to perform a task like this.

Any help would be much, much appreciated.

Answer 1

You can group documents using up to 2 columns (levels). If you have any such column which you can use for further grouping then it will be easier for you to apply out of the box grouping from library view.

Check below documentation for more information:

Use grouping to modify a SharePoint view