Hello mesch,
It isn't currently possible (within a single Hauptwerk configuration) to have more than one set of voicing per organ, but we do very much hope to add that functionality as a high priority in the future (also allowing linking sets of voicing and rank routing to different mixer presets). (Actually I had intended to include that in v5.0.0, but there wasn't sufficient time for it in the end.)
The only way currently that you could apply a different set of voicing for the same organ would be to use a different one of the Hauptwerk configurations ('Hauptwerk (alt config N)' desktop short-cuts), since all settings are entirely independent for each configuration. However, that probably isn't ideal, since all other settings would then need to be duplicated too. You can use the backup/restore mechanism for that to copy *all* settings, as covered in the "Backing up and restoring your settings and data: Copying your settings from one configuration to another on the same computer" section in the Hauptwerk user guide (pages 34-36 in the current v7.0 version).