@SimCher I had something like this happen to me when I first started playing. It is all in how you are saving your game. Each family does not need their own save file.. To go from being able to play each family in the same save file there is an icon in the upright right hand corner of the screen that is called Manage Worlds when you hover over it.. click that. From there, you can find wherever the other family lives in whatever town and click on their house to play them. There is also an icon in the upper right corner of the map world that looks like 2 people silhouette, if you click that, it will bring up the population of all the sims that are in the game. If you want all of sims to coexist in the same world with all of the same buildings and businesses they have to all be in the same save file.