How to use negative parts for unions using Basepart:UnionAsync?

So I want to make a script where it takes one part and a negative part (already in the game) and it unions them so there's a hole in the part from the negative part. When I try to do this, it unions the part and the negative part as if the negative part was just a normal part.

There may not even be a way to do this, but if someone knows please let me know.

local part = workspace.Part
local otherParts = {workspace.NegativePart}


local newUnion = part:UnionAsync(otherParts)
newUnion.Parent = game.Workspace