Close individual chats in Messages?

Before Mountain Lion, the Messages Beta allowed you to do command+w to close an individual chat from within the messages window. Now, that shortuct closes the entire chat window. Is there a keyboard shortcut that will close each individual chat? The only way I can see to do it is to control-click on the chat and choose "close chat." (Hitting the "x" deletes the chat and the chat history, which I dont' want to do.)