...
Given the flexible nature of this kind of permission, the proposal is to have this implemented as a role rule that can be extended using an openedx-filter. When checking for the relation between the Group TA and the learner, the platform can pass the user_id of both the Group TA and learner and the course key to the filter.
In a separate platform plugin, developers can write their own custom logic.
In the case of the Spanish consortium the plugin will check for the Group TA in the Course Team Management and their membership in the Teams. When the Group TA also belongs to the same team as the student they will be granted the permission to manage the grades.
This proposal will be refined by collaborating with the developers of the RBAC initiative. The ongoing conversation is being captured in the github thread:
...