Not putting @Rozza’s great work to trash 
and just adding some information about how you can get the email domain of the entered email. And for this you need a custom form and if you use a normal form you need to do this with a countdown on another screen!
Capturing user email domain - #3 by TKOTC ( JavaScript and Xano - posted by Steven )
Not assigning relationship to user from secondary table - #4 by Flawless ( Abracadalo - posted by Flawless )
And now you can do the conditions with this value.