I cannot have more than two different regional holiday calendars display on my calendar app, can this be resolved?

I would like to be able to display holiday 3 calendars in my iCal and have that sync across all devices. This seems like it would be a simple task, but it is not so. I followed the instructions here: View the Holidays calendar for other regions – Apple Support (UK)

It still does not resolve the issues. I want to display the Holidays for Russia (Europe region) and Japan (Asian region). If I want to see the Russia holidays I have to go to Settings>Language and Region>General to change the region from Americas to Europe. Then go back to the calendar app preferences and toggle the holidays tab on and off for the new region. This doesn't make any sense to have to do this every-time. In order to get the US holidays back, I have to change the region again repeat the process. Why can't I just have these holiday calendars under other and select them on/off as needed?

Can I have only one holiday calendar at a time? This doesn't seem right . Please help.