Can I choose the right collider?

You can only have one collider on one game object.

But what about this. Make an empty game object called say "spaceship"

Now make an empty game object with a sphere collider. And also make an empty game object with a cube collider.

In your hierarchy drag those two under the "spaceship". This means the spaceship is the "parent" of the other two.

Now put this script only on the cube collider object

 function OnCollisionEnter ()
    {
    Debug.Log("this is the cube collider speaking, and I got hitted");
    }

And put this different script only on the sphere collider object

 function OnCollisionEnter ()
    {
    Debug.Log("I'm Mr. Sphere I got bashed");
    }

Next. On the actual spaceship object, have this script, called TheBoss.js

 function Awake()
   {
   Debug.Log("the boss is running.");
   }
 
 function newsFromBelow()
   {
   Debug.Log("something happened underneath me!");
   }

So far so good! Finally in the script on the cube collider,

on a collision, do this

 transform.parent.GetComponent(TheBoss).newsFromBelow();

Maybe that will help.