I have implemented similar code before in Wordpress projects. The easiest way to do it would have the links go to a custom php page and in that page it will set the cookie based on the link. Then in your Wordpress header file you would just include a custom [login to view URL] file I that will check for an existing cookie and if it exists it will go ahead and redirect the user instead of showing the landing page.
I can have this done for you in a few hours. You would just have to insert your URLs into the [login to view URL] file, then drop the two php files into your website folder, add a php include to your wordpress theme header file, then just have the button links point to the one php file.