Rather than looking for a utility that will allow you to do these mass edits, you could avoid the whole issue by using a server side method to share the common parts of your pages in one file instead of many.
If your server runs PHP, you can change the filenames to end in ‘.php’, and include this bit of code on each page, to include a shared menu page…
[php]
include(‘menu.php’);
?>
[/php]
That way, menu changes involve changing only one file, and all of your pages are immediately updated.