I use often references which are chapters of edited books as it is often the case for conference proceedings.
I would be glad to link in a way the entry for the whole book with the entries of its individual chapters to ensure consistency within the entries and provide an easy way to update all the chapter data in one run.
This would require a relational database (which endnote is not) and complete rewrite of program which would make it impossible to be backward compatible, which I think is not a good way forward, knowing how many of my colleagues upgrade only every 2 to 3 years.