How to create a correct Unity package copy, which will not be replaced when you import?

I create a "Package 1" consisting of section A (unique) + section B (which will be repeated in all my other packages). This package works correctly is he is alone.

Next, I create a "Package 2" consisting of: section C (unique) + Section B (from Package 1).

To save time, I replaced the texture maps in the materials belong to old section A parts and replace this part on section C (directly on models in the Mesh.)

I renamed most objects in the scene and in the package as a whole. I delete all prefabs of «section A» and create prefabs «section C», because they are not pick up name changes. The prefabs of «section B», I left as is.

Now when I import «Package 2» in the scene that already contains the «Package 1», it begins the mess: «Package 1» Files are replaced by «Package 2», even them are named differently.

How to avoid it?

I can’t create each scene from scratch, unfortunately it will lead to the insane time-consuming.

Huge thanks for your support!