Add more than 9 calendars to a Group Calendar

Question

Could I add more than 9 calendars to a Group Calendar? I only have 9 colors.

I am using SharePoint 2013,

Answer 1

You can add one more calendar into the Group Calendar but cannot beyond the 10. Because their is limit which is hard coded into the SharePoint code and you cannot change it.

If you have more than 10 Calendars then create another Group Calendar to adjust the remaining.

OR if you want then use the 3rd party tool. SharePoint Calendar Rollup

Here is SharePoint Code, thanks to Trevor:

public ICalendarAccessor CreateAccessor(string type)
{
    if (this.m_allIds.Count == 10)
    {
        throw new SPException(SPResource.GetString("CalendarAggregationLimit", new object[0]));
    }
    ICalendarAccessor accessor = this.CreateAccessor(type, Guid.NewGuid());
    this.m_allIds.Add(accessor.Id);
    this.m_accessorMap[accessor.Id] = accessor;
    return accessor;
}