a plugin for a private chat area?

Hi

I am not sure if I will explain this clearly but will give it a whirl.

Basically we have some pages that are for clients and these are password protected. What we want to do is incorporate a messenging area on these pages so we can post a message and then the client can respond and visa versa, kind of like a forum but would not need topics or anything like that. We thought of trying to add a blog category for each client and make posts that way but of course every new post will be shown on our main blog page which we dont want.

The reason behind this message system is that we want an electronic copy of correspondence available to both us and client available 24/7.

If anyone has come across anything like this please can you give us a shout

Thanks