Waiting for parallel batch scripts

Question

I have 4 batch files. I want to run one.bat and two.bat at once, concurrently. After completion of these two batch files, three.bat an

Answer 1

Just adding another way, maybe the shortest.

(one.cmd | two.cmd) && (three.cmd | four.cmd)

Concept is really straight forward. Start one and 2 in paralel, once done and errorlevel is 0 run three and four.