I am in favor of updating the major styles that would need this to be accommodated (e.g., MLA, Chicago), combined with a test case illustrating expected data structure for such an item.
For creators, CSL currently relies on the heuristic that editor and translator refer to the editor/translator of a container if one exists. The cases where this is a problem are fairly rare, rare enough that I’m not sure they are worth pursuing unless a hierarchical data model is adopted. I would expect the same heuristic to apply here: the editor of a book with a container-title is the editor of the container. The editorial-director variable is also available (it’s used in primarily French styles to distinguish the person coordinating the curation of the book contents from persons doing textual editing).