Graham,

If you map the CCs in your RadioButtonsExample document, you can greatly simplify the coding:

Private Sub Document_ContentControlBeforeStoreUpdate(ByVal ContentControl As ContentControl, Content As String)
Dim oXMLPart As CustomXMLPart
Dim oNode As CustomXMLNode
  Set oXMLPart = ContentControl.XMLMapping.CustomXMLPart
  If Content = True Then
    For Each oNode In oXMLPart.DocumentElement.ChildNodes
      'The first character of the title and node name identifies the set (i.e., "A" or "B")
      If Left(oNode.BaseName, 1) = Left(ContentControl.Title, 1) Then
        If Not oNode.BaseName = ContentControl.Title Then
          oNode.Text = "false"
        End If
      End If
    Next
  End If
lbl_Exit:
  Exit Sub
End Sub