Hmm, bookmarks can only exist once in a document so you can't bookmark the second region with the same bookmark name. You could append a digit to the related bookmarks and adjust the code to also look for extra digits in the bookmark name.
Alternately, you could move away from the bookmark method of tagging areas for hiding and use other content controls for this purpose. The benefit of using Content Controls for your tagging is that you can loop through CCs which share an attribute like Tag or Title. For example
Code:
Dim aCC As ContentControl
For Each aCC In ActiveDocument.SelectContentControlsByTag("Hi")
aCC.Range.Font.Hidden = True
Next aCC