Delete previous Document version on Release

Hi, we have an unusual scenario where we do not keep copies of old documentation, for "legal reasons". Currently document management is done on shared drive, I want to move this documentation into Windchill and version control it and release through workflows etc etc. But we cant keep primary content or attachments in previous versions. So, is there a way that we could trigger the previous versions primary content to be deleted after a new version is released, or just delete the previous version completely?