How do I create a collaborative webform using Webforms? How can I create a webform that allows users to collaboratively fill out a webform built using the Webform module in Drupal 7?

The users are building their own webforms, which works great to populate text and content. Some forms should allow several users to collaborate on filling them out. Basically, they will be to-do checklists where each user will mark tasks complete. This is a single submission edited by multiple users.

I could write these checklist type forms using the Forms API, allowing the users to maintain the forms themselves has proven much more efficient for getting forms published.

I am open to modules that extend Webforms or even other modules that fit the requirements better. However, I would like to stay with Webforms because my users are already comfortable with it.
I have been able to share a single submission with a role. 

First, enable the 'save draft' option in webform Advanced Settings The 'Save Draft' option is here: webform/configure -> Advanced Settings -> Show "Save draft" button

Then, create a role with 


'Access all webform results'
'Edit all webform submissions' 


permissions. Any user assigned to this role can edit a submission started by another user.

The edit submission link (node/%/submission/%/edit) will be shared with the appropriate team members.