Hi ,
We have analyzed your query. You can set the custom calender by using custom scheduling. To know more about custom scheduling please refer the following link,
UG Link: http://help.syncfusion.com/ug/wpf/gantt/default.htm#!documents/customschedule.htm
Our GanttControl enables you to mark the custom regions in GanttChart area using Striplines. To know how to add strip lines in GanttChart region please refer the following UG link,
UG Link: http://help.syncfusion.com/ug/wpf/gantt/default.htm#!documents/striplines.htm
Please let us know if you need further assistance.
Regards,
Riyaj Ahamed I