Role Based Access: access madness between a Limiting Collection and all Collections which use it

1. In order to grant the Helpdesk rights to manage membership of Collection A, I must assign them the Modify right on its Limiting Collection B.
2. Review any other Collection configured with Limiting Collection B and realize that Helpdesk's rights allow them to undesireably modify membership.

How can I ensure the Helpdesk personnel can only manage memebership of Collection A without creating a unique limiting collection that will only be used by Collection A? I cannot create a unique limiting collection for every single collection I need to granularly delegate rights to! That's insanity!

born to learn!