How to use Bulk/Mega sign to require both parents to sign a document

[Claudia25586948i0pz]

I need to send a waiver to the parents of 300 students.  I need both parent signatures.  How do I do this with the bulk send?  I can send the document separately to each parent but I want to send to both with both of their signatures required and the waiver not completed until signed by BOTH parents.