How to change the order of same rank nodes in Graphviz?

Question

I'd like the column a ... i to be the first column from the left and a1 ... f1 the first column from the right. I tried to setup same rank, different weights, but with no luck. How can I control the order of columns?

digraph G {
  newrank = true;
  node [shape=record, style="rounded,filled", color="#5F6368", fillcolor="#F7F7F7", fontname="Arial", fontsize=10];
  graph [fontname = "Arial"]; edge [fontname = "Arial"];
  style = "dashed";

  subgraph cluster0 {
    color="#34A853";
    a; a1; b; b1; c; c1; d; d1;
  }

  subgraph cluster1 {
    color="#EA4335";
    e1; f1;

    subgraph cluster2 {
      color="#FBBC05";
      e; f; g; h; i;
    }
  }

  a -> b -> c -> d [color="#34A853"];
  a1 -> b1 -> c1 -> d1 [color="#4285F4"];

  edge[style=invis];
  {rank="same"; a -> a1 [constraint=false]}
  {rank="same"; b -> b1 [constraint=false]}
  {rank="same"; c -> c1 [constraint=false]}
  {rank="same"; d -> d1 [constraint=false]}
  {rank="same"; e -> e1 [constraint=false]}
  {rank="same"; f -> f1 [constraint=false]}

  d -> e -> f -> g -> h -> i;
  d1 -> e1 -> f1;
}