You can definitely set some pages to Private. Once you create your site, you can go to the sharing and permissions tab on the dashboard on the left-hand size of the page. Then, go to the top right of the page and click on the “enable page-level permissions.”
Once you have done that, then you can click on each of your pages and either use the user permissions already set up for your site as a whole, or make individual pages private and then add specific users who can access the page. Hope that helps!