The common idea is that gravity can't be shielded against. I highly doubt that.
Let us create a sphere: $$s: r^2 = x^2+y^2+z^2$$ which is centred on a point $M$.
Now we start putting tiny black holes all over this sphere and increase their number to infinity. We now created a bowl of black holes, which is empty in the middle. Now any outside information cannot pass the bowl. Therefore any outside gravitational force cannot apply to something in the middle. Of course, this bowl is collapsing, but since we can choose $r$ this does not matter (ugh, does not matter?, it is all about matter). Assuming we would put a body in the middle, this body would not feel any force but its own weight, when r is only big enough.
Could this idea, theoretically, shield against gravity? I consider that changes in the structure of the sphere should make no impact at all...
I think the abstraction of this question is: What will happen to gravitational information when stopped by a black hole.
EDIT: This experiment does not contradict Newton's third law since also the inside of the sphere cannot apply force to the outside.
It does not matter, that the sphere can be stretched as long as we presume that it cannot be torn up. If we choose $r$ big enough, we will feel this stretching since it can only be stretched with the speed of light. If we would now imagine that we would have the heaviest thing possible outside the sphere, which would without the sphere apply massive force on us, we have shielded (for at least some time) against its gravity.