Send same documents to multiple people, based on input

I run a summer camp.

I have a (yes....) 9 page form that every parent/student needs to fill out.  However, their group leader must sign it, as well as the parent(s), and even their Region leader in some cases.

Problem I have is- the Group leader is different in every case.  So, when the parent fills out the form, I want them to supply the group leader's email address, and have the system KNOW it needs to route the signature to the group leader.  

Is that possible?

So, the flow is:
I upload the forms package once.

Johnny Doe (or parent) fills out the forms, enters his mom's Email address, group leader's email address, and if needed, the region leader's email address.   Once he submits it, I see it is submitted, read and approve it (making sure it is filled out right).   Then it automagically routes to the parent, group leader, region leader (if needed), and comes back to me with all signatures.

Since there are blocks for both mother and father's signatures, if they enter both, it would go to both.  If they don't enter mom's but do enter dad's, it would only go to dad.

Thanks!