Plugin to password-protect urls of WP pages?

Hi – Is there a plugin that would simply block certain urls of a WP sites?

I’m working on a site that needs to give some member visitors access to additional member-only pages (a listing of properties). I’ve tried a number of “Intranet” solutions but it’s only hiding the body part (description text area) of these member-only pages, not the widgets, not the slideshows, sidebars, related properties, etc. I want to be able to block everything on those pages for non-members.

The additional layer of complexity is that there is a second group of members and each of these can only see their own listing (one post/page).

What I’m hoping to find is easy plugin that could simply manage a list of usernames/password each given access to specific urls on this website.

Thanks!