Unfrotunately such scenario has not been supported by WebScheduler. 

However, after discussing this issue with the developer, a workaround would be to hide the event which shown in the holiday date. This could be achieved using OnEventBound client side event handler by comparing the event date and holidays, if it match set the css style of the event so the event will be hidden. Here is the snippet:

function WebScheduler1_OnEventBound(controlId, evt)
{
    var sched = ISGetObject(controlId);

    var evtDay = [evt.StartTime.getDate(), evt.StartTime.getDay(), evt.StartTime.getFullYear()].join("/");

    for (var i = 0; i < sched.Holidays.length; i++)
    {
        var hDate = sched.Holidays[i].Date;
        var hDateStr = [hDate.getDate(), hDate.getDay(), hDate.getFullYear()].join("/");
        if (evtDay == hDateStr)
        {
            evt.Element.style.display = "none";
        }
    }
}

If we just hide the event as suggested, the schedule will not be correct.
Let say my TotalRecurrence = 10, then 1 of the day fall on the holiday.

It's still scheduled, but it's hide during displayed, so the schedule displayed will be 9 recurrence not 10, which is incorrect

Another issue will be, my users are from different institution.
Let say i have 10 institution, then my system will have 10 database, so each institute will have their own holiday, be it public holiday or institute holiday, so i cannot insert the holiday at application level.
Let say 5 institue login at the same time, then system will bind all holidays from 5 institute to the same application, then 5 institue will c the same holiday, which is incorrect

Pls advise!

Thanks!

I have discussed this issue with the developer and unfortunately, we do not have a workaround for the TotalRecurrence issue. Using the workaround from the previous post the TotalRecurence will not account for the holidays and the total event displayed will be less than the TotalRecurrence pattern.

Regarding holidays from external database, you will need to buffer the list in a HTML hidden input and match the holiday list with the event start time during the OnEventBound client side event handler. There is no workaround to hide the individual recuring event from the server.