As a Nikon View user I have come to like the ability of that program to set the file's read only and hidden file attributes. This provides an easy way to transfer a selection from one program to another.
For instance, if PM could recognize read only or hidden file attributes, then I could make a selection in Nikon View, mark them as read only, open PM, select the read only images, and perform a PM action on them.
Of course, the read only and hidden file attributes have other -- more conventional -- uses as well.
If implemented, then PM should be able to select files by attribute.
When in RAW+JPG mode, setting a file's attribute would set the raw, jpg, sound, xmp, etc. versions of the file to that attribute.
When reading attributes in RAW+JPG mode, if either of the raw or jpg files were marked read only or hidden, I would suggest that the file by displayed as read only or hidden.
Deven