Security **How to limit acces"


In the Htaccess/WebDAV I created 6 directories with each a specific user name and password. There are 6 module … if I give the module 1 user and password, I not only access the module 1 but also have automatic access to each and everyone of the 5 others !!!
How can I have specific and separate access for the 6 modules that each contains a large quantities of files and specific download for each module ?