Can you track webinar registrants that were forwarded the link from a friend and tie that to the original email recipient?

I am trying to find out more information about a specific "refer a friend" campaign. We are ultimately trying to incentivize the audience by sending an email asking them to forward our email to friends and encourage those friends to sign up for our webinar. The plan is to somehow piece together when someone registers for the webinar and person that forwarded them the email with the registration link. Is this possible?