Very well
This is my category list. I use it to add my own tags associated with genre and content in each of the documentaries. I have only just started, so I only have the categories needed for the movies I've seen so far, but I will add more as I need them:
Now lets try and group by category:
Which looks like this:
I then sort by rating and look under Science:
Even though I have given the episodes "No Ordinary Genius" (which are really independent from all the other documentaries in BBC's Horizon series) categories Science and Physics, it does not sure up under Science and Physics, but stay in "Undefined" because I have not categorized / put on genre tags on Horizon because it is impossible as each documentary in the series is a unique subject.
Another aspect of the same problem with the episodes is following:
When grouping by rating, the episodes does not show up under 6-8 which is where they belong with a rating of 8, but under "not rated" because I have not rated the Horizon series as a whole, which is impossible.
So you see, the big problem is that PVD treats all "TV series" as though you should be able to rate the series as a whole, and to specify it's genre as a whole, which in the case with normal TV series and documentary mini-series is totally possible, but not decade-longtime running documentary series such as BBC Horizon or PBS Nova. But these gets imported from IMDB as big-ass TV series with many, many episodes! I don't know what can be done or what the smartest thing is to do. The easiest thing in terms of easy of implementation would probably be my suggestion in the first post, although the best/most complete solution would be have PVD distinguish between two different kinds of movie series, the normal kind that is currently available, and a second kind, whose episodes have properties much more like single-movie-entries, just brought together under a single TV series name. Does this make sense?