No force can be shielded fully, but that's fine, because we can make the other forces smaller using distance of time averaging or averaging over many repetition etc like we do in other physics experiments.
A scattering experiment in which we send entangled masses to fly by each other and measure their interactions sounds very possible, even if it is very hard technically.
And how would you do that?
If we had a way to shield a region of space from gravitational influence from something else we'd have a very useful technology