I'd recommend just asking the user to confirm the email domain they care about. I solve this on YesGraph's registration page indirectly just by making the entry

I'd recommend just asking the user to confirm the email domain they care about. I solve this on YesGraph's registration page indirectly just by making the entry field label "work email". https://www.yesgraph.com/signup/ https://www.yesgraph.com/signup/