Hello ljos,
The Playback will render the track content internally to the universe it was originally recorded from. However, in the settings page, you can select which internal universe is mapped to the output. So, lets say you originally recorded some track using universe A, then DMX port D can still output the track content, by selecting 'Universe A' for Port D in the settings page.
Keep in mind though, the output from the different running playbacks will be merged. Hence, if you record all tracks only using universe A, and play the tracks back simultaneously by multiple playbacks, it results in all running tracks merged in universe A. Probably, you want to record the tracks that should run simultaneously, in separate universes, or at least such that they don't interfere with each other.
Hope this answers your question.
Best regards,
Jurrien