If you wish to filter on the time only, then you should specify FilterMemberPath
to be the Time representation of the original DateTime value. If you do the same for the DataMemberBinding, then you will also see only the time displayed. One way to do so would be to directly specify the DateTime.TimeOfDay property.
As another approach you can expose a new property of your business object to represent the time and use it instead.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.