ActiveDEMAND has a fantastic system for requiring users to enter a password to access landing pages.
This password system can also be used on your WordPress site. With the ActiveDEMAND WordPress plugin installed, you will see a tab called 'Access Control'
This exposes the defined contact password custom fields to the website and allows you to define areas of your website that are restricted based on the specific custom fields.
Each custom field can have its own set of access rules. The plugin uses the custom field's defined 'login' URL as the redirect when someone tries to access a page that is restricted by a specific password rule.
You can use regular expressions in your rules as well. Thus if you do not want someone to access any pages below a specific set of pages in a hierarchy, you can use a rule like:
This will ensure all pages that have a URL that starts with 'example' will require a valid password. thus
etc will all require a valid password to access.