how to use group policy to control IE 11 visit one website only?

Good comment Dave. But I need a solution.

proxy is a  solution. But I prefer group policy solution.
Thanks much Maclean, John and Dave.

Could block all on proxy but allow site to bypass proxy via GPO. Bit of both that way. Otherwise there is no solution via GPO.

Have you looked at the one site you want to limit the access to and checked to see if it would work?  If it is a public site, we can check for you.  

Note that if you do this, you will have to disable all addons to IE11 because many of them 'phone home' when you open the browser.  When I opened my homepage on my HP laptop with Fiddler running, I saw that the HP Network Checker add-on 'phoned home' without me doing anything.

I'm assuming that you want this to apply only to IE11.  Many programs 'phone home' to check for updates and of course, Windows does too.  They just don't do it thru IE11.

Thanks much for all your help. Much appreciated!