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 http://daybase.eu/ or http://www.timeanddate.com/services/api/holiday-api.html 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.