public class Nested { public string Name {get; set;}="Имя"}
public class Overall { public Nested One {get; set;} = new Nested(); public Nested Two {get; set;} = new Nested(); }

<local:Overall>
       <local:Overall.One>
              <local:Nested Name="Ваня"/>
       </local:Overall.One>
       <local:Overall.Two>
              <local:Nested Name="Иванович"/>
       </local:Overall.Two>
</local:Overall>