<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=383585) </details> <!--IssueSummary end--> Documentation: - [sharing projects](https://docs.gitlab.com/ee/user/project/members/share_project_with_groups.html#sharing-projects-with-groups-of-a-higher-restrictive-visibility-level) - [shared groups, API](https://docs.gitlab.com/ee/api/groups.html#share-groups-with-groups) - [sharing groups](https://docs.gitlab.com/ee/user/group/manage.html#share-a-group-with-another-group)