At the studio we have to be able to maintain and work collaboratively with a large number of files. For those who are interested, I made a little tour of the system we have set up as well as the process within Blender to link in groups from other .blend files.
Word of caution: when working with files that reference other files, be *very* careful with filenames and filepaths! Moving files around or renaming things can result in quite a headache.
Edit: Here’s a link to Blender-aid, the content management tool for Blender I mentioned in the video.