Hide companion files and turn them into a status icon

I am using Directory Opus for showing thumbnails for my video editing work. See the attached screen dump RskildeAir01x. The editing program is the well known and much used Sony Vegas video editor.
Sony Vegas generates a file with a .sfk extension for every media file (video or audio) used - and so the pros are that it is possible to see which files are already used in the current project.
The cons are that every used file has 2 thumbnail icons and so you can see less media files per screen page.
Of course one could ask DO to skip the .sfk files - but then again you could not see if is a file is used or not.
We are talking of directories with several hundred media files.

A great wish is that DO would not show the .sfk files - but instead mark the corresponding media files thumbnails somehow - like simply by drawing a red dot in the upper right corner or a small ribbon or whatever showing that the files are used in the project already. See example RskildeAir02x.

Maybe such a feature already exists ? or - if not - would it be possible to make ? and would somebody do it ? - or are there better solutions to this wish ?

Best regards
Einar, Copenhagen

It could be done via a generic shell extension (to change the icons depending on the companion file; then filter the other files normally using Opus), or via an Opus-specific VFS plugin (which could provide a custom view and custom icons for the folders). Both are fairly technical things to write, though (typically written in C++).