Hi Chris,
Just go to Overview > View Details in the Contract Workspace template you're working in, it will let you create an approval task in there that is attached to the entire workspace. One of the options in the approval task says "Repeat for Each Document Draft". Select "Yes" on that option. Since the Approval task is attached to the entire Contract Workspace and not just a document or Folder, any time you amend the workspace (other than the administrative amendment) it will force the project owner to push the workspace through the approval task again.
Let me know if you have any other questions.
Thanks,
Sean