Correct interconnection method

slurry bowl

nterconnection question. Where in the code does it say this is not allowed? I cant find anything clear in 230.82(6) or 705, but I know its not. The correct way to interconnect needs to be on both sets of conductors, possibly by inserting a terminal box before the (2) 400A discos, interconnecting there, then feeding the (2) 400A discos. thanks.