SharePoint calendar problems: Merge two calendars into one.

I have created two custom calendars(A & B) contaning multiple overlayed calendars in both. Now I want to merge the two calendars into one (C) by overlaying A and B. But i can't get it presented correctly.

The way it should look like

this is how i want it to look:

Calendar (A) - overlayed view calendar

When I remove the duplicates in calendar A & B in "modify the view" --> Show items only when the following is true: --> "blank value" they get showed as they should. But they disappears in the overall view (Calendar C)

calendar C - after duplicates is removed