Member Only Area – setting up a password

We have our site under WP 2.5 up and running. We have our public access area which works good and wanted to have a Members Only area for sharing internal business amongst our members. Looks like this:
Heading
Public 1
Public 2
Public 3 … etc
Members Only
Members 1
Members 2
Members 3 … etc.

The Members Only area was supposed to have protected sub-pages under it for all the various Members Only topics. I thought that by passwording the Members Only “switchboard” we’d be able to safeguard the child/sub-pages under it. Apparently I’ve not done it correctly because we discovered that anyone can call up those Members Only sub-pages even though you get prompted for the password for the switchboard page. IOW, people can blow right past the switchboard. What did I miss in the tutorial on child pages and providing or limiting access to them only by way of the switchboard? How do I limit access to Members 1, 2 & 3 without having to password each of them?

Thank You.