WordPress multi domain – redirect

I’m afraid that this doesn’t have much in common with WP, but…

One of the way to solve this would be to put iframe on page B and set its source to site A. So in site B you do something like this:

<html>
  ....
  <body>
     <iframe src="http://dominoA.com/landing-page" style="position: fixed; top: 0px; left: 0px; bottom: 0px; right: 0px; width: 100%; height: 100%; border: none; margin: 0; padding: 0;">
        Your browser doesn't support iframes
     </iframe>
  </body>
</html>

You could also use CNAME record, I guess…