Password for each group

I agree as long as a master password can be used as well.  Here's one idea:  When locking groups, have radio buttons (checkboxes) for each group, as well as a button to select/deselect all.

Funny, I just posted this very suggestion. As far as master passwords are considered, I'd want it to be something that doesn't prompt me. For instance, if I elect to have the "Popular" group open to the public, and the "Work" group protected, I don't want to be hassled to enter a password just because I clicked newtab/home/whatever you've set to open speed dial. I only want to be prompted for a password when I click a protected group.