Allow a course to be set visibility to a specific Sub-Account.

I am creating resources for our K-12 county, I want to make a course visibility for everyone in the "County Resources" sub account. This would prevent access from students who are not enrolled in that sub-account.

This could have many uses when you don't want everyone in the institution to have access, but you don't want to enroll all of the group (in this case the faculty) in the course.