You can use the Schedule Downtime feature to deactivate alerts during the holidays - http://pubs.vmware.com/vfabricHyperic50/index.jsp?topic=/com.vmware.vfabric.hyperic.5.0/Schedule_Downtime_for_a_Resource_Group.html .
But I don't think there is a way to configure a role to receive alerts based on a holiday calendar.