There are certain categories of patrons that should not be selectable by any libraries: Self Check, SIP Accounts, Testing, Admin, etc. It would be great if when staff are adding new patrons, they don't have to sift through those categories which they shouldn't use. We can narrow it down to one library, but not none. I would suggest that we have an option in the libraries for Admin only (superlibrarian) or we have a check box to hide the category except for superlibrarians.
It sounds like you'd like something like an "internal use only" checkbox you could check when creating a patron category? And then maybe a sub-permission under 'borrowers' for adding or modifying patrons with that category?