Allow event to be in several calendars

I find myself having to duplicate events that make sense in several calendars (like a meeting between several teams for example) and it would be nice to just say that I want this event in several calendars and any modification to it is visible in all those calendars.

The way event are currently linked to calendar (parent/child relationship) would be hard to refactor but we could imagine an implementation based on several documents synchronized with each other each in a different calendar.