Only able to save 5 families on Sims 4 PS4 version

On The Sims 2 for PC each neighborhood was a save game, and you could have different households in each neighborhood, right? But you could only have one copy of each neighborhood. You had one save game which was Pleasantview, another one that was Strangetown,... You could have 2 families living in Pleasantview, which could meet each other, but Sims living in Pleasantview couldn't meet or visit Sims living in Strangetown.

In The Sims 4, each save game is a copy of all neighborhoods - each save game is a copy of the world (contains all neighborhoods). Having 5 save games, you have 5 copies of the world: 5 Willow Creek, 5 Newcrest,... You can have different households in the same world, and now Sims living in Willow Creek can meet Sims living in other neighborhoods, as long as they are part of the same savegame, as long as they live in the same copy of the world.

In The Sims 4, when you start a new save game, you are creating a clean new copy of the world. You can have more than one household in the same save game, but for that you need to create the new households in an existing save game, instead of creating a new save game.

If you load one of your save games, you see the world map, right? Now that you are inside that save game, instead of loading your household (let's call them Family A), use the option you will find in the right bottom corner of the screen to create a new household in that same save game (Family B). This new household will live in the same save game than Family A.