I am not trying to split up the community. HN is global and this is good. BHN is local and also focused on showing local startups. That being said it can't obviously have every hour 200 new submissions. It is more about sharing your experience in Berlin and getting to know the Berlin startup scene. I honestly think that submissions will stay on the front page for ~1 week and this is also how it was calculated.
I was not counting for BHN to be on the front page so I am trying now to fix all the small things that pop up.
Edit: As I mention in te FAQ this is an experiment and if people continue to contribute I will try to push it into a direction that makes it valuable for everyone interested in Berlin.