This series design was part of a restoration project for a very large 50+ sermon series that had poor audio. As the series was remastered with high-quality audio restored from original tapes, the series was also divided into five sections to make it more accessible to casual listeners.
The concept for this design was to clearly link together all five sections with a shared spine. When lined up together the sets have a complete image of a family, but when by themselves have only part of the image. The implication is that you will not have a complete understanding of the purpose and organization of the institution of family without the entire series.
The shared spine also has a value-added aesthetic benefit for those who have the entire series, and the combination of five separate CD packages makes the full set appear to have more value than one single case.