I want to add a system to my game similar to the housing system in a lot of RPGs. I want players to be able to purchase/rent properties with in-game currency. I also want these houses to exist separately from the rest of the game world, and act sort of like their own "server" or gathering place. I want players in multiplayer to be able to access their friends' homes, and I also want to make these homes customizable.

And what is your question?

Yes you can do this and it isn't a real difference from existing technics. Maybe you take a look at google for some resources?

7 hours ago, Eraz said:

I want players to be able to purchase/rent properties with in-game currency

Like any other "buy an item" shop mechanisms, this is similar except for that the item should only be sold once so you need to double check if the item/house is still available. Maybe you place a sign inf ront of it that players need to touch so comes first serves first.

7 hours ago, Eraz said:

I also want these houses to exist separately from the rest of the game world, and act sort of like their own "server" or gathering place

It is like you enter an instance like you do in other games. Again no magic but you should look for resources about how different games implemented that yourself

7 hours ago, Eraz said:

I want players in multiplayer to be able to access their friends' homes

Instances can be joined in most online RPGs

7 hours ago, Eraz said:

and I also want to make these homes customizable

This depends on the kind of customization you want. Like in The Elder Scrolls (not online) you can obtain different houses and get furniture packs on different merchants that enable certain predefined and preplaced assets or even build your own house from predefined meshes. Or you let them place there stuff like they want, makes it a little bit more difficult but not impossible as you only need to store the item-id and transform in that players house data sheet in your database for each item he/she put there. Anything else is like well known editor mechanics, Fallout 4 has had or Neverwinter Online

Thank you for explaining it. Sorry, I should’ve been more clear with what I was asking, but your explanation clears everything up. I’d been having trouble finding things on google about this, so I overthought it and I thought I’d need some crazy complicated network of multiple servers. Your explanation simplifies it so much and is really helpful, thank you!