The code needed for that is essentially the same as maintaining two different versions. There's really no way to implement this automatically since each trainer has different stuff for each game. To buy trainers individually please visit CheatScapes:
Link
[Edited by Neo7, 3/27/2013 5:14:07 PM]
Yeah just one problem it will be up to the trainer creator to keep the program updated, if the trainer isn't updated by the creator the person buying the trainer may have a different version of the game then the trainer in turn making the trainer incompatible with the game itself. What then? A lot of people don't updated there trainers programs with some goes to buy the trainer the version of the game doesn't match the version of the trainer. For instance there's a game called NFS: MW (2012) that I'm playing and I just went to look up a trainer for version 1.5 on cheatscapes.com however, I am unable to find a trainer for that trainer yet and you guys haven't given the trainer to cheatscapes.com yet.
[Edited by Autosonic10, 3/28/2013 9:55:26 AM]