Some time ago PC Pilot ran a review of VoxATC and added that a new version costing about

Hello Graham,VoxATC is working on the use of multiple voices so that it can be set up that no voice talks to itself so yes, it's not available yet but work on it continues, can't give you any details of the usage or release, just stay tuned, we're working on it, RegardsLion JanssenVoxATC Beta tester

Thanks Lion :)