'Children' of Narrative Folders

If we create a Yes/No property for something, we can have it tick off the parent as completed when all the children are completed. Great so far.
This doesn’t work so well for Narrative Folders. The events (or whatever) in those folders aren’t children of the folders (unless created that way, but there can only be one parent and I like nesting events). So, when all the ‘children’ of the Narrative Folder are complete, the folder must be marked off manually.
I’m not saying this is an urgent feature I can’t do without, but it would be nice if we could have a tick box to make completed events complete the folder they are embedded in. If that’s possible.