Hiding pages

I am running a website for a student group. Obviously, there are pages that we don’t want the public to be able to see readily, but I am having trouble hiding those pages from the side bar (I don’t have much experience in PHP).

Currently, all of our private pages are password protected, but the links are still visible to anyone. What I would like to do is have the private pages hidden, with the exception of a member parent page. When someone go to the members parent page, they will put in a password. After the password is put in, they will be able to see all of the private pages, even if they are no longer on the member parent page.

Is there an easy way to do this?