You can now control how much of the schedule your contractors see.
Head into your settings using the drop down menu.
When you are in your settings click on the grey "Contractor Login View" sub-tab.
There are two boxes. If they are ticked they give your contractors the ability to view all the tasks in builds and view notes in builds. This is how you control what your contractors can and can't see, if you leave "Ability to view all the tasks in builds" unticked then your contractors will only be able to see their own tasks.