Yes, this is possible. I mean I have not tried it myself, but I see n reason why this should not work. However, it would also be possible to create plain rigid bodies and use
body = BulletRigidBodyNode('...')
body.setCollisionResponse(False)This raises/clears the btCollisionObject::CF_NO_CONTACT_RESPONSE flag, which controls if a collision object should not only detect collisions, but also respond to collisions. At least if I understand the Bullet API right.