Switch between two webpage

I have a web page which we will call index.php and another which we will call index2.php. I want an admin to be able to switch between the index.php page and the index2.php page by clicking on a button so that only one of the two is visible on the web. The two pages are on the same server and I can use a mysql db. The admin will get to the page with the button via another login page with user and password.