Duplicate check at the user registration page

Hello All,

We are implementing B2C/B2B/BOB webhsop for one our client.

In Standrad B2C webshop , duplicate check is performed at the user Id level during registration.

Can the duplicate check be performed at any other place for example Email id, Address etc of the user?

If anyone has worked on the same scenario, then kindly provide the configuration documents for the same.

Regards

Sanjib Paul