Graphviz - Box positioning Problem - graphviz

Question

My structure has two main chains with side nodes in sub graphs. Every thing looks nice but when i close the two chains all the boxes in the sub graphs jumps to the right side.
At the end of my code you can remove the "I"->"J" then you can see the best what I mean.
I am not a native English speaker, sorry about my English and I am a graphviz newbie.
digraph G {
size ="6,6";
node [color=black fontsize=12, shape=box, fontname=Helvetica];
subgraph {
rank = same;
"b"->"B"[arrowhead=none];
}
subgraph {
rank=same;
"c"->"C"[arrowhead=none];
}
subgraph {
rank=same;
"e"->"E" [arrowhead=none];
}
subgraph {
rank = same;
"f"->"F"[arrowhead=none];
}
subgraph {
rank = same;
"g"->"G"[arrowhead=none];
}
"0" -> "A" -> "B" -> "C"->"D" -> "E" -> "F" -> "G" -> "H"->"I";
"0" -> "K"->"L"->"M"->"N"->"O" ->"P"->"1";
subgraph {
rank = same;
"L"->"l"[arrowhead=none];
}
subgraph {
rank=same;
"M"->"m"[arrowhead=none];
}
subgraph {
rank=same;
"N"->"n" [arrowhead=none];
}
subgraph {
rank = same;
"O"->"o"[arrowhead=none];
}
subgraph {
rank = same;
"P"->"p"[arrowhead=none];
}
"1"->"J";
"I"->"J";
}
and with "I"->"J"; removed:

Answer 1

This is how I'd go about it: Create a cluster for each main chain with its side nodes:
digraph G {
size ="6,6";
node [color=black fontsize=12, shape=box, fontname=Helvetica];
subgraph[style=invis];
subgraph cluster0 {
A -> B -> C -> D -> E -> F -> G -> H -> I;
edge[arrowhead=none];
{rank = same; b->B;}
{rank = same; c->C;}
{rank = same; e->E;}
{rank = same; f->F;}
{rank = same; g->G;}
}
subgraph cluster1 {
K -> L -> M -> N -> O -> P -> 1 -> J;
edge[arrowhead=none];
{rank = same; L->l;}
{rank = same; M->m;}
{rank = same; N->n;}
{rank = same; O->o;}
{rank = same; P->p;}
}
0 -> A;
0 -> K;
I -> J;
}
Resulting in: