Option Explicit

Public Event Changed(ByVal OldValue As Long, ByVal NewValue As Long)

Private m_lValue As Long

Public Property Get Value() As Long
 Value = m_lValue
End Property

Public Property Let Value(ByVal NewValue As Long)
 Dim OldValue As Long
 OldValue = m_lValue
 If OldValue <> NewValue Then
    m_lValue = NewValue
    RaiseEvent Changed(OldValue, NewValue)
 End If
End Property

Option Explicit

Private m_Items As Collection 'внутренняя коллекция

Public Event ItemChanged(Item As CMyItem, ByVal OldValue As Long, ByVal NewValue As Long)

Private Sub Class_Initialize()
 Set m_Items = New Collection
End Sub

Private Sub Class_Terminate()
 Set m_Items = Nothing
End Sub

Public Function Count() As Long
 Count = m_Items.Count
End Function

Public Sub Add(Item As CMyItem, Optional Key, Optional Before, Optional After)
 'Добавляем во внутреннюю коллекцию новый экземпляр класса-оболочки
 Dim ItemNotifier As New CMyItemNotifier
 ItemNotifier.Init Me, Item
 m_Items.Add ItemNotifier, Key, Before, After
End Sub
 
Public Sub Remove(Index)
 m_Items.Remove Index
End Sub

Public Function Item(Index) As CMyItem
 Dim ItemNotifier As CMyItemNotifier
 'Вытаскиваем из ссылки на экземпляр класса-оболочки ссылку на элемент
 Set ItemNotifier = m_Items(Index)
 Set Item = ItemNotifier.Item
End Function

Friend Sub NotifyItemChanged(Item As CMyItem, ByVal OldValue As Long, ByVal NewValue As Long)
 'Friend-методы не видны за пределами проекта.
 'Передаём событие элемента наверх.
 RaiseEvent ItemChanged(Item, OldValue, NewValue)
End Sub

Option Explicit

Private m_Items As CMyItems 'ссылка на хозяина-коллекцию
Private WithEvents m_Item As CMyItem

Private Sub Class_Terminate()
 Set m_Item = Nothing
 Set m_Items = Nothing
End Sub

Private Sub m_Item_Changed(ByVal OldValue As Long, ByVal NewValue As Long)
 'Вызов Friend-метода хозяина, который, в свою очередь,
 'делает RaiseEvent, т.е. передаёт событие на более высокий уровень
 m_Items.NotifyItemChanged m_Item, OldValue, NewValue
End Sub

Friend Sub Init(Items As CMyItems, Item As CMyItem)
 Set m_Items = Items
 Set m_Item = Item
End Sub

Friend Property Get Item() As CMyItem
 Set Item = m_Item
End Property

Public Sub Release()
 Set m_Items = Nothing
End Sub