I have 2 content types: Courses and Documents. In Documents there is a node reference field which connects it to Courses (actually with a Node Reference URL Widget). In Courses there is a user reference field.
I'd like to add permission of Document content creation only the user who is referenced in Courses. Is it possible somehow? I tried it with Node access user reference modul (it has a "Grants for referenced users to create content" option) but it adds the create permission in every Course content, not only in that he/she is referenced.