Youtube for EDU Alternative Ideas

We are transitioning to a FortiGate 600D and we are wondering if there are alternative ways to setup or redirect student Youtube traffic to https://www.youtube.com/education.  We accomplished this with our old content filter by using our Youtube for EDU 22-digit code.  Unfortunately, when we copy and paste that code into our new Fortigate, it doesn't operate correctly.

Google's Youtube for EDU section hasn't worked since late 2014 so we can no longer obtain a new EDU code to use in our FG.  Google's replacement Youtube filtering option is DNS redirection, HTTP headers or Manage via Google Admin Console.  These options do not provide the group level filtering that Youtube EDU redirection provided using the YT EDU Code.  

I was wondering if there is a way to redirect traffic to the Youtube for Education website for certain Web Filtering groups.  A custom URL concept seems the easiest to setup but I don't know if that can be done in FG's Web Filter configuration.

What have others done to redirect all traffic for one URL to another?

Thanks,

Zach