Default to previous conversation upon login

My studio is aimed for young people. Ideally I want to restrict them to one conversation within my pickaxe. At the moment it defaults to a new conversation upon login and users have to navigate in the menu back to their previous conversation thread, adding complexity to the process.
Any suggestions?

There’s no way to default them to the old conversation at the moment. It will start a new conversation every time unless they specifically click into one of the old conversations.