Please add to the "Library" window  column with file extensions. In cases where you want to add many files with the same extension to a shared folder where there are a lot of files with different extensions. This would make it possible to sort all the files in the folder by their extension and quickly select to add (or exclude) them for sharing. To do this you need to add a context menu for the selected files - Add to sharing (if they are not marked for sharing) or Exclude from sharing (if they are currently sharing). And this context menu should work either for all groups or for a specific group.
It is now very time consuming to select individual files one by one that are in the same folder in order to add them to sharing.