If you "Input" CCs are mapped and all tagged "Input" then you could use something like this:
Code:
Private Sub Document_ContentControlOnExit(ByVal CC As ContentControl, Cancel As Boolean)
Dim strComposite As String
Dim oCC As ContentControl
Select Case CC.Tag
Case "Input"
For Each oCC In ActiveDocument.ContentControls
If oCC.Tag = "Input" Then
If oCC.XMLMapping.IsMapped Then
strComposite = strComposite & " " & oCC.XMLMapping.CustomXMLNode.Text
End If
End If
Next oCC
MsgBox strComposite
Case Else
End Select
End Sub