If you run a single course in cooperation with one or more colleagues, you can add them as co-instructors to that course. Thus, the added people have access to a single, but not all of your courses. You can do this by accessing the "Manage Co-Instructor Rights" button while you have selected your desired course.
Then you can invite your colleagues via their email addresses and monitor the status of your invitation. Once the invitation is accepted, you are able to work together on a course and create sessions.