Jiapa

I'm not sure if there's a mod for this already or an option to switch, but... I'm sometimes a bit possessive about my galaxies after I've spent so bloody long playing with them. In Civ, I could keep playing after winning. I could go take over those last few holdouts; finish that last special project, colonize that last colonizable terrain. Once the game has registered that you won, does it HAVE to end? I mean, I've been known to delay the ending longer and longer, declaring