Duplicate events

I am combining numerous calendars - work Outlook, employees Outlook, family Gmail, personal Gmail, wife's Gmail and even another work calendar on Gmail as we transition. A couple of the calendars show duplicate events when I sync certain joint events (manually or using an external app). One calendar should be smart enough to see a duplicate and give me the choice of which calendar displays it, hiding the other. The duplicates often have identical information.

As it is, the calendar looks overly full because of duplicate series'.