I would like to be able to write all posts to Site A, which is a central site covering all topics. I would then like to have sub domains B,C,D and E which cover specific topics to pull posts from Site A. In other words, I would only have to enter posts a single time in Site A no matter what the topic, and all other WordPress sites would be updated depending on their topic through use of tags, categories or whatever.
I have looked at MU and at WP Hive, but haven't seen this kind of solution. Is this possible with WordPress?