Save your development time by DirectChat Client & Server. Both of projects created using C/C++ (Win32 API) with purely DirectPlay code. It's not only a simple chat room, you can create chat group in Game Server and the players can join the they wanted group. This package included both of Client and Server workspace. You can apply it to be a simple or multigroup chat room, messenger-like application, or games such as Poker, BlackJack or another board game that you want to grouping support.
This software is a commercial software. You will be able to download and test DirectChat Client/Server during a certain period of time, then, if it does what you need, you will have to acquire the full version from DirectChat Client/Server publisher. The DirectChat Client/Server - free trial version has a size of 78 Kilobytes.
For additional information and support request, please contact directly DirectChat Client/Server publisher.

DirectChat Client/Server Screenshot