Having recently learned about the Casimir effect I began to wonder about spacetime and the effect of intervening bodies on gravitational forces:

Does a mass have a "shadow" behind it or some sort of "dampening" effect on gravitation from body C as sensed at point A with body B in between?

In relation to the Casimir effect, if there is some sort of "dampening" effect, then gravitational changes (e.g., a pair of rapidly-circling stars) might produce an additional force between two bodies which are close together where the changes are diminished (or possibly amplified?) in between the two bodies. Has any such force been measured or given research time?