Use Marketo ID to select Lead to Update on Form Submission
Standard behavior seems to be to use email address to determine whether a lead exists so it can be updated or created as appropriate. Is it possible to use any other field such as the Marketo ID to identify which lead the form should update?
So for instance, if I have 2 email addresses, and Marketo has email address A, but when I go to a form, I submit it with Email address B, that's going to create two leads for the same person rather than updating the preferred email address in the existing lead. Any way to avoid that if I can know the Marketo ID (or some other unique identifier), and I'm able to pass it into the landing page via a query string parameter?