Collision Detection without Dynamics response

[slavik262E]

I'm using Bullet for dynamics in a flight simulator I'm writing. However, I also would like to use it for sensors. I'd use a cone-shaped collision object as my radar cone, and when other planes collided with the cone, I would make them show up on the player's radar. However, I obviously don't want other planes bouncing off the radar cone. My initial research pointed at using collision masks, but then I noticed something in the wiki:

Note: As of 17/08/10, collision masks must match both ways for there to be a collision. The above example is incorrect. If WALL collides with NOTHING, it will actually collide with nothing even though PLAYER is set to collide with WALL. WALL must collide with PLAYER and PLAYER must collide with WALL for there to be a collision.

In a btDynamicsWorld, is it possible to have collision detection between a btCollisionObject and a btRigidBody without a response from the rigid body? Would a Ghost Object be the solution in this case?