How add new Sub procedure to Items of List?

[a1024]

Hi...

How add Sub procedure to Items property of CustomClass
example

Dim aa As New myList

aa.Items.Add("abc")
aa.Items(2).Xy '<<<<< Xy


-----------------------------------

Class myList

    Private _Items As New List(Of String)
    Property Items() As List(Of String)
        Get
            Return _Items
        End Get
        Set(ByVal value As List(Of String))
            _Items = value
        End Set
    End Property

End Class