Add Per-User Group Package Access Control

Currently, if you own a package you can give individual users edit permissions for that package. If a package is owned by a group however, you can only assign certain group ranks edit permissions. I would like to be able to manage per-user permissions for group-owned packages. This helps me in situations where I have a large code library with unrelated modules saved in packages, and I want collaborating scripters to only have access to the parts of my codebase relevant to their work.