Okay, so I logged in to check in more detail what those are.
In the editor these seem to be file contents organized by a file organizer plugin. However the issue is that I can’t see any connection between the folders and the files in terms of taxonomy or custom field values.
My guess is the file manager is probably using a custom way of organizing the files and not taxonomy terms nor custom fields.
With that I don’t think this is possible with any plugin out there – unless there is one specifically made for this. My initial thought was to select the files to search and restrict them by folder, but the folders are not taxonomy terms nor custom fields so it is not possible.
I’m afraid this is not doable with a ready made plugin, I’m sorry.