Ajax project - Same url but differnt content

I currently have a website templated in SMARTY. When first time visitors visit the homepage ([login to view URL]), they are redirected to another php page that starts a series of php pages to collect info. This info filters the site so they will only see content that interests them. Once they have made their selections, a cookie is set and they are then sent to homepage. On the next visit and on every subsequent visit, they are sent directly to the homepage. THE TASK: i want to create an ajax module so when first time visitors visit the homepage ([login to view URL]), they are NOT redirected to the previous series of pages, but instead, they will see the same series of pages as on overlay or as the actual page content. However, they will still see [login to view URL] in the browser. Once the info is collected, the cookie is still set and on the next and subsequent visits, they will only see the index page with normal content