Appointments+ Automatically import holidays

Hey Guys and Gals,
I'd love it if I could just check off from a list of working day exceptions, see my mockup below. Jewish or Muslim holidays are hard to translate to Gregorian, but there are computerized calendars easily available for example or and even for Gregorian calendar holidays, most users I think would appreciate being able to check off "Canadian Civic Holidays" etc. (maybe a bootstrap multiselect type control would be better)

Thanks for considering my request.