475771 auto login button from one site to the next

Good Day All, I'm currently building a website for a client of mine that's an airline carrier in the caribbean. The site is being created in joomla. My client now wants something special done to the site. Every now and again they offer specials to different group of people on the island and around the world. What he will like is for these persons to be able to view the specials in a page that is created by an IBE system.. Here's what has to be done. A button has to be created on the home page of the website. When a user clicks on the button of the website, a script has to be run that will auto populate the username and password on this website.. [login to view URL] .. After it populates the fields, it will then auto log-in to the page where the person can view the flight / root specials. Can this be done?