Unfortunately this sounds like a limitation of Outlook. In other words this is a “feature” not a “problem”. You can always submit a feature enhancement request to Microsoft though!
I was looking for a bunch of VBA macros to ventilate my main calendar to several calendars and have them in a group, but not from different users, just my own., – timelines of billing, personal and public meetings … tech. projct management, etc.
ventialtion on color categorization seems a good basis. Searching, I hope to find something to do the trick, but searching for ‘Features’ is potentially time wasting and code reuse (Min.coding), is the order of the day 😉