Nova - Resources using "child" resource that has values

Hopefully I can explain this well enough. I have the following Models:

Organization User OrganizationUser (gives User access to Organization). This is a many to many OrganizationUserRole (OrganizationUser and Role). OrganizationUser can have 1+ Roles Role (defines all the roles that can be used in OrganizationUserRole)

Here is what I'm trying to accomplish and cannot figure out how to do:

On the OrganizationUser EDIT page,

1. Show the OrganizationUser details but not editable (just show the OrganizationUser ID, OrganizationUser Organization ID, OrganizationUser User ID)
2. Show the roles and allow these to be assignable or removable for the OrganizationUser, but the updates need to happen against the OrganizationUserRole.

Thank you for your help!