Physics Collision detection

Hey there.

I'm trying to start a space game but physics is making me crazy.
I hope someone could give me a way to do what I want because after a lot of tests, nothing is working like I want.

Here is what I have: The player is in the spaceship A, and this spaceship is in spaceship B. The spaceship B is the reference point so he is always centered at zero coords but he is moving in the scene( the scene translates, not him). I'm trying to find a way to move the player inside A; A which is moving in B. The problem here is collision detection for the 3 objects.

At the moment for spaceship B, i set it as a rigidbody and in a LateUpdate I translate ever objects in the scene by his position + his velocity, in order to let it at zero. It allows me to collide with scene objects. And for the player and spaceship A I don't know how to script them.

Is there a way to do it ?

I think i may put that on a pic.