Individual household calendars?

I'm sure this has probably been requested before, but the ability to create a calendar for an individual household - as opposed to one calendar per save file across all households and worlds - would be greatly appreciated! Especially for rotational players, because currently when I move between households (which I do, regularly), I find myself having to edit the single calendar again - and again - and again - or else face a bunch of sad sims when a holiday is cancelled on them because it doesn't fit with the story/beliefs/origins/whatever of their household.
Because holidays are celebrated differently across cultures and so require different traditions across households; sometimes you want one household to have a vaguely faith-based holiday that's at odds with the faith of another household, and your household composed of two sweet elders that have been together for years and live in a little bungalow for their twilight years don't want to spend their New Year's Day holiday the same way their grandchildren three lots away do: by taking a polar bear dip into an outside pool.

A general save file or world calendar would still be pretty good for the people who aren't interested in individual household calendars, and for being the 'default' household calendar full of holidays that all sims celebrate.