Problem

The plans permissions should work like project permissions and anyone with the "Advanced Roadmaps user" global permission should be able to grant permission to their plans to any Jira group.
For instance adding a testgroup to the Advanced Roadmaps user permission. However this does not mean this group can now be added to individual plans permissions. It still depends on whether the user adding the group is actually a member of this group. To reproduce:

1. Add some groups to the "Advanced roadmaps user" permission
2. Add a non-Jira Admin user to some OTHER Jira groups (without the Advanced roadmaps permission)
3. Give this user the "Advanced Roadmaps user" permission (not by adding one of their group but by adding the user)
4. Log in as this user
5. Create a new plan and go to this plan → Settings → permissions
6. Change the edit permission of this plan to "restricted" and try to add some groups
   The groups which have been added to the global Advanced Roadmaps user permission will not be visible. Instead the groups of which the user is a member will be visible.

Suggested Solution

The plans permissions should work like project permissions and anyone with the "Advanced Roadmaps user" global permission should be able to grant permission to their plans to any Jira group.

Why This Is Important

In plans, those project group users would need to be members of every single business team/group to be able to grant them plan permissions. In large companies, this is not feasible.

Workaround

No workarounds at the moment. One will be added here once available.