AutoCAD .NET :: Custom Menu In Default ContextMenu Group?

I have code that adds my own custom menu group to a contextmenu when right-clicking with a particular object selected (in this case a dimension).  Works great!

My questions are:

1) How can I get my custom menu item located where I want it rather than appearing where it wants in the contextmenu?

2) Can I add my own custom menu item to an existing context menu group?  For example:  It you right-click on a dimension string in AutoCAD 2012, you get a group of dimension commands: Dimension Style, Precision, Etc...  Is it possible to add my menu item to that group?  If so, how can I do this.  I cannot seem to find it documented anywhere!  Below is my code for adding my own menu group.
 
Private Sub AddObject_RightClickMenu() Dim ed As Editor = Application.DocumentManager.MdiActiveDocument.Editor Try m_ObjectMenu = New ContextMenuExtension m_ObjectMenu.Title = "Dimension Objects Menu" Dim mnuItem As MenuItem = New MenuItem("Extension Line Toggle") AddHandler mnuItem.Click, AddressOf run_dimExtEdit_WhenClicked m_ObjectMenu.MenuItems.Add(mnuItem) ' create an rxclass Dim dimensionClass As RXClass = RXObject.GetClass(GetType(Dimension)) ' adding the object menu Application.AddObjectContextMenuExtension(dimensionClass, m_ObjectMenu) Catch ex As System.Exception ed.WriteMessage("Error Adding Object Menu: " + ex.Message) End TryEnd Sub