Hey LuAnne,
The only way to pull off something like this would be to use The Events Calendar and then our iCal Importer plugin.
Each calendar generates and iCal feed, and so you could install the iCal Importer plugin on your “main site” where all of the events should display—set up some automatic imports from all of the calendars you want to import, and the iCal Importer will pull the events from those disparate calendars into the one main calendar.
To see this in action and learn more, check out the product page for iCal Importer here: https://theeventscalendar.com/product/ical-importer/
You do NOT need anything other than a Personal license for your needs here, and do NOT need any other add-ons like Events Calendar Pro or anything. You only need The Events Calendar and then the iCal Importer.
This is the only method to approximate what you describe here; other than this, the only way to have all events on one calendar like you describe would be to perform manual imports and such.
Cheers!
George