Put some pressure on it, like "You all have a chance to get 3-4 posts in, if your business isn't wrapped up within that time there will be a timeskip. Feel free to finish it up with a 'pre-timeskip' post but please finish it quickly." kinda thing.
Look, I'm giving you all a chance to do this, but there is going to be a time-skip. I have a lot of better things planned for this RPG besides this moment, and it isn't going to be the only bonding moment you're going to get. There is going to be a kingdom to unite and some sweet revenge to get on after the Redcliffe thing. As a starter, go ahead and make friends, prep, and converse with one another. My XO has spoken, and those will be the guidelines.