Can I make it to where only certain groups of users see certain courses?

Step 1) Create a User Group

People Tab > Groups > New > Assign Group Name and Group Parent (If applicable) > SAVE

Step 2) Create a Course, Assign the Course a Name, then Click Permissions

Step 3) Assign Permissions to Course by User Group for View and Register, then click SAVE

Now, the users in the specific User Group will only be able to view and register for specific courses.