Each calendar group will render its timeslots based on the OwningResource of the SelectedCalendar of that CalendarGroup. The working hours are resolved first considering the DaySettings for the Resource, then the DaySettings for the XamScheduleDataManager, then the DaysOfWeek of the Resource, then the DaysOfWeek of the XamScheduleDataManager (off its Settings) and then finally based on the WorkDays and WorkingHours of the XSDM's Settings. So if you're asking if you can have per Resource working hours then yes you can do that. If there are date specific (including recurring) settings then you would define those on the DaySettingsOverride of the Resource or if you just want to define them for specific days of the week regardless of the date then you can just do that on the DaySettings of the Resource (e.g. using the WorkingHours).