If you just wanted to do a small test, “Welding” is supported in UE4-
https://docs.unrealengine.com/latest/INT/Engine/Physics/PhAT/UserGuide/index.html#welding
For anything as detailed as Minecraft, you could look at integrating/copying existing free code. But the short answer is no, it’s not possible because it’s not coded into the engine already. Setting up 10 000 physics cubes might be slow… well, maybe it’s possible.