Automated Email Form to Second Unknown Signer?

I've been looking for a solution to this but haven't found an easy one using Adobe Sign out of the box. Here's the scenario.

A student signs a form for student aid but needs a parent signature also. At this point the student fills in his parent's email on the form but when he submits the form it gets sent to the parent to sign. Neither of the users and email are known beforehand because we'd like to use an embedded form on an internal, password protected  website (except the parent can be sent to the link to Adobe because they wouldn't have a student ID to login to the student portal where the initial form is).

Can this be done easily in Adobe Sign using a widget?

Or does this need API customization - if so how?