I am using a contribution list to allow users to create/update/edit documents. I need to allow them to do the same to the child documents. For example, I have a doc type of Property, that can contain multiple Unit doc types underneath. Is this something in the configuration that I can set up or do I need to customize the contribution list or create a custom form control? I need to allow editing of the units as well as the property for the users on the front end.