What you can do is to manualy delete content from for example blah.php and add following code:
<?php
header("Location: http://www.your_site.com/blah/blahblah.php"); /* Redirect browser */
/* Make sure that code below does not get executed when we redirect. */
exit;
?>
You can make redirection to the first (or any other) page in the sub level.. This is just how I do it, and by doing this (removing WB code from .php file ) you lose option to menage this page via backend..
cheers