I believe with the recording methods that an be turned on via configuration you can get one recording per stream. Via the Java API it should be do-able to send a stream to multiple recorders to achieve what you are saying.
If you don’t need the smaller recordings right away, it would be pretty straightforward to fire up a tools (ex. ffmpeg) at the longer recording and split it into shorter VODs.
Wowza can chime in here, but I believe its one recording per input stream. (At least if you are configuring it– there are definitely ways to do this with custom code)