using Additional field on MVC 5 Authentication

Is it possible to add additional field on MVC 5 identity Authentication?

Currently as by rule same email address can't be use more that once (which completely make sense as userid)

But is it possible to add extra column with combine primary-key with username. so that same email address can be use multiple time with combination with company code.

company  : <companycode>
username : <email address>
password : <password>