parallel --link cmd ::: A B ::: C D
Will run cmd first with parameters A and C and then B and D. Without --link you get full permutation which, if I'm reading your question correctly, is not what you want.
parallel --link cmd ::: A B ::: C D
Will run cmd first with parameters A and C and then B and D. Without --link you get full permutation which, if I'm reading your question correctly, is not what you want.