Add additional filetype to a specific "Kind" In Finder one is able to group the files by kind. For example "Movie" kind groups .avi, .mov together. I would like to add additional file extension .mkv to the list of "Movie" kind. Is it possible? 

As a bonus, it would also be interesting to know if, similarly, it is possible to add additional "kinds" of files.
The reason this is happening is answered here, https://superuser.com/questions/371892/osx-assign-extension-to-content-kind

Unfortunately, there isn't a really fix for the problem.