The desired behavior could be achieved through RadCalendar control which is part of RadDateTimePicker. As you don't have direct access to the Calendar ( because it is placed in a popup), you should customize the template of the DateTimePicker and edit the Calendar inside. You need to subscribe to the DisplayModeChanged event of the Calendar and to disable the YearView in its handler.
Please see the attached sample project for a reference. In it we've used Implicit Styles
to style the DateTimePicker as this makes such customizations easier.
Hope this helps.