Automating Holiday Alert Muting for Select Applications

We are in the Financial industry, and would like to solve for alerting during US Holidays. There are a selection of disparate app monitors across several different nodes that Ops does not want alerts for during Holidays. Outside of creating a manual task via Unmanage Utility (and I mean "manual" because we would need to manually set the date for each holiday), does anyone have any suggestions on how to accomplish this via Custom properties? We can mod our alerts for look for something like A_MuteHoliday = True at applications.customproperties, but don't have a good solution yet on how to make the alerting engine "date aware".