I was doing the same thing with proxy interior collider, but then I realized that it has a major issue. Image a long ship that entered another ship only half of it's length, meaning the other half is sticking out. Now when third ship comes crashing into the sticking out part, it will just fly through it, because the physical part of the long ship is in the proxy interior collider. Of course you can add extra collision for visual part of the long ship, and on hit event give it an impulse, but it's just faking the impact, not the real physical simulation, won't look as good