Public courses from a noguest moodle

Our VLE is set.up primarily to give our students access to course resources, however it has been taken on by some research groups as collaboration space. Some of the groups are interested in making their areas public and allowing people without accounts access. The difficulty arrises because we want to be able to quickly change courses between 3 levels of access - closed : enrolled students and staff only preview : any student or staff has read only access public : open to external visitors as guest We presently use the 'guest' faculity to provide the preview access within a closed (no guest/google) moodle. Couple of options come to mind: 1. Close all courses to guest access, and then enable preview access using role overrides at category or course level. The enable public guest access. 2. Pinhole for specific courses by tweaking login and require_login() function. (If only there was a hook, or I was confident enough to install php pecl runkit) 3. Create a paralled networked moodle, where public courses can be hosted with different permissions Number 3 looks like the way we are going - a networked moodle means that we can give our internal users permissions to manage their courses, and also permit guest access or self registered users in a more public space.