Use Active Directory accounts for Wordpress website access and page viewing

We have an existing Wordpress website, hosted publicly on a third party web server. We need to enable our company active directory users to login to the website. The Active Directory server is hosted internally in our network. We also need the active directory security groups to be replicated somehow in wordpress, so that we can control page visibility based on user group. Requirements: - Advise us on how to connect Wordpress to our AD (suggest a plugin, suggest how we enable our external website to talk to our internal AD - you can liase with our IT support office on this) - Implement the AD connection for users - Implement the AD connection for user groups. We're currently using a wordpress plugin called User Role Editor which enables us to create custom user accounts seperate to the regular Subscriber, Author, Editor, etc.. - you may use this or something else. - Implement per page access control based on user group. We're currently using a plugin called Wordpress Access Control that allows us to make pages only visible to certain user groups. Use this plugin or an alternative. - This should work with custom post types, as our existing theme (called Manual) has several post types. The above plugins already support this, so work with them or alternative solutions. You need to be available between 8am and 5pm GMT10+ for liasing with our in house staff.