Develop a WordPress Plug In

I need to develop a WordPress plugin or may be this is some script changes that allows the following:

Currently user comments can be turned on or off to posts and pages and the collective comments from all registered users gets displayed beneath the post/page.

I want the ability to only show the comments made by the user when they are logged in and responses made by the Admin to that user. In this way we can develop a 'chat' all be it not live around the post/page.

Where I want to get to is being able to publish a page with a question within the content, for the user to comment on the question, for the admin to respond to the comments form the user so that there is a thread of discussion based upon the question.

When a different user logs in they should see the page with a blank comments field and not see any of the discussion/comments from other users even though they are visiting the same page.

I hope that is clear. But please ask me any questions you need for further clarification.