Google Verify Your Account

Hello,

I am looking to reactivate 3 Galaxy S6 phones for our work. The issue is I cannot get passed the Google Verify your Account because I do not have the previous employees gmail info. I brought these to the sprint store and they could not delete or bypass this Google security. Is there anyway to get passed this account after the device was reset if you do not know the previous account that was synced to the device? I have no issue with clearing whatever contents the phone currently has if that is what it takes.