When you're looking for mods or cc for your game, please post in the appropriate wcif section (after reading the guidelines there, which point you to resources you should search first). Also, please be aware that MTS doesn't have a forum for requests.
I would normally move this to wcif for you, but in this case there's no point: there is no mod that makes it possible to have multiple independent households on the same lot outside of Apartment Life. (For people interested in how AL works: you are allowed a maximum of four playable apartments per lot and the game treats each apartment occupied by a playable Sim as its own sublot. So each occupied apartment is its own savepoint with its own timeline, just like any other residence.)
However, it is not clear to me that this is what you would want for an orphanage, which is typically a community-living environment. Perhaps you could explain how your orphanage is supposed to work?
There are mods (like Inge's
keys at Simlogical) that allow you to set up apartment-like rules for doors in your game.