Need to password a “group” of pages in WP 2.6.2 –

We have our blog 2.6.2 and it’s running fine. There are two “area” let’s call them public and private. Public is an area where the masses can go and look/post etc. Private is an area reserved for members of our Society. Private has about 8 pages of Members Only topical material. I need to show Private but hide the child pages from the public with a password only Members would know. I want to avoid using the traditional “Username/Password” duet and simply want to have the Member click on Private over in the sidebar, be presented with a prompt for “Password”, enter password and then the sidebar would open up further to reveal the Member’s Only pages so they can click and read etc. Flexi-Pages plug-in almost gets it but as soon as you click on Private, and although the password is prompted, all the Members material gets revealed in the sidebar without use of the Password. The Members Only link in the sidebar has its attributes set to “passworded” page in the admin. The Members only pages are child pages of Private.

Questions:
Conceptually, is my basic design flawed? Am I going about this the wrong way?

After searching and wading through hours of plugins, directories, hompages, can’t find what I need – is there one (a password only plugin or widget) that someone can point me to please? And if not, then can someone just tell me if I’m into trying to “hand-code” or roll my own plug in?