@MPoovie You do in fact have separate saves, which is why the two families aren't showing up at the same time. Each Sims 4 save is its own standalone file, separate from and not influenced by anything you've done in other saves, even ones that take place in the same world. So you could, for example, play in Sulani for a dozen generations, and then start a new save in Sulani and see all the original townies and none of the sims you created or that were born in-game in the other save.
To have the two families in one save, you'll need to save one family to the in-game library and place it in the other family's save. Load one save, go to Manage Worlds, click on the household, and save it. Then quit the game (always a good idea when switching saves), reload, open the other save, go to Manage Worlds, find the library copy of the household you saved, and place the family in the house of your choice. The two families will now coexist, and they'll be able to visit each other normally.
You'll need to rebuild the relationships of the family that you save to the library and place in the other save: the sims won't know anyone except each other. If that bothers you and you don't want to put in the time to fix things through play, there are cheats you can use to set relationships however you want.
@MPoovie I am sorry I never got back to this, I didn't notice the notification for this thread until now. You are in good hands though. 🙂
