You don't need to be a novice to be confused by what you are trying to achieve. This is pretty advanced stuff and less than 5% of Word users would have any idea on what we are talking about.
I've been working in a vacuum somewhat because I have no knowledge of how Trados interfaces with the Word documents but now I've seen the old file I can make much better assumptions about how you might game the system and code a solution to lock those parts of the file.
If you used the New file but removed each of the CCs that you added in your testing (right click and remove CC) then the following macro would group all the grey areas
Code:
Sub GroupTags()
Dim aRng As Range
Set aRng = ActiveDocument.Range(0, 0)
With aRng.Find
.ClearFormatting
.Font.Color = wdColorGray50
.Replacement.ClearFormatting
.Text = ""
.Replacement.Text = ""
.Forward = True
.Wrap = wdFindStop
.Format = True
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False
Do While .Execute
aRng.ContentControls.Add (wdContentControlGroup)
Loop
End With
End Sub