Proper way to use assets to allow for updating your packages later on?

In Unreal Engine, when you "import a package", you can create a "child instance" of each object that you change and place that in a separate directory, so for example - let's say I purchased and imported an asset from the store called Purchased Asset that had 3 files in it named Script1, Blueprint1, and Animation1.

Now let's say I want to change the Blueprint1 and Animation1 for my game, I could create child instances of those two files and place them in my game directory so it looks like this:

 Assets
   Purchased Asset
     Script1
     Blueprint1
     Animation1
 My Game
   Blueprints
     Blueprint1 (child of Assets -> Purchased Asset -> Blueprint1)
   Animations
     Animation1 (child of Assets -> Purchased Asset -> Animation1)

You can modify the Blueprint1 & Animation1 in my game directory and then whenever I update the Purchased Asset, my changes don't get overridden - but the base classes still get updated, so I get whatever bug fixes and/or new features the developer added. It's kind of like a symbolic link that remembers changes, or inheriting a class - but for GameObjects as well...

Is there an easy way to do this in Unity? What would be the proper way of referencing asset packages so that they could still be modified by you, updated by the author, and not break your game?

Thanks!