Perhaps the question is whether managers need to be admins? Admins by definition would be the one to do any sort of customizing and anything to do with admin interface, so no this is not really something that would be possible (ie: a custom plugin that an admin would install, or a theme component/ CSS an admin would setup?). To me, it sounds like Managers should be category moderators or a custom group? What admin level access do managers require to do their role? Perhaps you can expand a bit more on the use case.