public class Inner
{
    [Range(10, 20)]
    public int InnerProperty { get; set; }
}
public class Outer
{
    public Outer()
    {
        Inner = new Inner();
    }
    public Inner Inner { get; set; }
    [Range(10, 20)]
    public int OuterProperty { get; set; }
}

public class TestModelBinder : DefaultModelBinder
{

    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        if (bindingContext.ModelType == typeof(Outer))
        {
            Outer outer = new Outer();

            //Three different tests here:

            //outer.OuterProperty = 15;
            //outer.Inner.InnerProperty = 5; - this is suposed to be an error, but its not
            // For above configuration, ModelState.Keys.Count = 0

            //outer.OuterProperty = 5;
            //outer.Inner.InnerProperty = 5; - this is suposed to be an error, but its not
            // For above configuration, ModelState.Keys.Count = 1 ( OuterProperty)

            outer.OuterProperty = 15;
            outer.Inner.InnerProperty = 15;
            // For above configuration, ModelState.Keys.Count = 0

            ModelBindingContext newBindingContext = new ModelBindingContext()
            {
                ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(
                () => outer,
                typeof(Outer)
                ),
                ModelState = bindingContext.ModelState,
                ValueProvider = bindingContext.ValueProvider
            };
            return base.BindModel(controllerContext, newBindingContext);
        }
        else
        {
            return base.BindModel(controllerContext, bindingContext);
        }
    }
}

ModelBinders.Binders[typeof(Outer)] = new TestModelBinder();

[HttpPost]
    public ActionResult Test(Outer tme)
    {
        bool isValid = ModelState.IsValid;
        return View();
    }