[Endoperez]

It might be possible to make a new .map file in which you defined the pretender of the nation of your choice to be the one with whom you won your Last game. That might not work, though, because with modding tools some restrictions were added to prevent that happening in multiplayer games.
Remember to modify the scales too, and starting dominion power, if you can do this. Otherways it takes them from the latest god you created for the nation...