I am in the process of preparing a newsletter and I am just wondering if there is an application out there that allows me to customize the group of contents of my newsletter to a specific set of users. What I am trying to accomplish is to have group of contents ( content A, content B, etc…) in my main newsletter. Then the application will allow me to specify a specific group of content to a specific set of users. For example, set of users 1 will receive content A and B; set of users 2 will receive content A and F, and so on. Currently, I do everything manually and it is a pain in the neck. Thx