Always open the last privat chat session

What would I have to change to disable the “chat invite” process for privat chats and always go to the last chat between the two users? If it is the first chat session than a new one should be created…

I guess most of the functionality is already there since each page reload is kind of doing this.

We are using this plugin for a small community so there is no need for this process really…

Thank you for the help!

Michael