Programming 2 Volts to work with 1 remote

Has anyone successfully programmed 2 or even 3 Volts to work with one remote? My immediate family now owns 3 Volts (two 2013's , and a 2014), and I would like to carry one remote that works all 3 cars. I know the mechanical key won't work all 3, but just having one remote that will electrically work with all 3 cars would be a lot easier than carrying 3 remotes. I could swear that I read a post at one time that detailed how to do this, but after hours of searching tonight, I can't find any posts on this subject, other than some comments that it should be possible.