We are using about a dozen dedicated calendars for different categories of events.
This separation is necessary for access rights reasons.
However, various external people (not NC users) need read-only access to the combined calendar view which shows the aggregated dates of all calendars.
I can enable link-sharing for one calendar at a time, but sending about a dozen links to those external people and expecting them to combine those calendars on their own just to get the desired overview is a no-go. 
I am relatively new to nextcloud and have searched the docs and forum for solutions or hints thereto, to no avail.
I have also tried several workaround ideas that came to mind - like, “first subscribing the calendars from another NC account and then sharing them there”, or “embedding them into one view” - so far, nothing works.
Does anyone know how to share the combination of all (or several) calendars by one link, or otherwise can suggest a workaround?
Thank you very much in advance!
(latest NC, latest calendar)