[Marco van Herwaarden]

As these are simple webpages any access control will need to be done on the level of the webserver (apache/?). So i doubt you can get away without using a .htaccess. I am not aware of any modification that will (automatic) restrict standard webpages based on vBulletin user(group)s.

You could however obfuscate the pages by making the directory not indexable and add something random to the filename/path. Only those with access to a thread in which these URL's are posted would have access. But that only works until someone shares them with others, so not much bulletproof.