Creating Web Form to Accomodate Variable Signers

In Adobe Sign, is there a way to solve this issue:
I've created a web form where a paralegal will fill out all of the fields and then select an attorney from a drop-down list (with export values of their email addresses if that helps). I would like to make that selected attorney become the first signer of the form (as in, they become the next destination in the flow before heading to the static supervisor and admin) during the filling out without my intervention. But that attorney won't be known until the paralegal is filling out the form.
I've tried Conditions where the Signature box should only appear if "Jane Doe" is selected from the drop-down (and carries the "jane_doe@email.com" exported value). Multiple, overlapping Signature boxes with matching Conditions for all of the choices from the drop-down either don't work or I'm doing it wrong.

I've added all possible email addresses to Counter-Signers.

I can't seem to make it work.

Is there a better method or does Sign support variables that would solve what sounds like a common occurance? Thanks.