graphviz (DOT) node alignment and merging arrows for flow diagram

thanks up-front for taking the time to read this and any help or advice.

I am new to graphviz/DOT and am trying to create a flow diagram, but I am having trouble with node alignment.

Here is what I have managed so far, however, what I would like is for all of the diamond shape conditionals and the oval "Fail" to be vertically aligned, with lines from the right hand side of each diamond merging into a single arrow to the left of the "Do some thing" oval, but I haven't managed to figure it out or even figure out whether it's possible with Google results.

I have tried many different variations of subgraphs and ranking.

• concentrate, not compound
• used ports (https://www.graphviz.org/docs/attr-types/portPos/) and group (https://www.graphviz.org/docs/attrs/group/) to position and align nodes
• workaround for subgraph edge assignment

digraph {
  //compound=true;  // does not apply to this graph
  concentrate=true

  node [group="main"]  // lazy way of assigning group to most nodes
  request [
    label = "Request";
    shape = rect;
  ];

  {
    rank=same;

    successful [
      label = "Successful?";
      shape = diamond;
    ];

    done [
      label = "Done";
      shape = oval;
    ];
  }

  condition_1 [
    label = "Condition 1";
    shape = diamond;
  ];

  condition_2 [
    label = "Condition 2";
    shape = diamond;
  ];

  condition_3 [
    label = "Condition 3";
    shape = diamond;
  ];

  condition_n [
    label = "Condition N";
    shape = diamond;
  ];

  fail [
    label = "Fail";
    shape = oval;
  ];

  do_some_thing [
    label = "Do some thing";
    shape = oval;
    group=Gz
  ];

  {
    done [group=gX]
    request -> successful;
    done -> successful [label="Yes"; dir=back];

      successful:s -> condition_1:n
      condition_1:s -> condition_2:n
      condition_2:s -> condition_3:n
      condition_3:s -> condition_n:n
      condition_n:s -> fail[label="No"];

      condition_1:e  -> do_some_thing:n // [headlabel="Yes"]
      condition_2:e -> do_some_thing:n //[label="Yes"]
      condition_3:e -> do_some_thing:n //[label="Yes"]
      condition_n:e -> do_some_thing:n [headlabel="Yes  "]
 

/************** this should work, but you hit a bug  
    {
      condition_1:e
      condition_2:e
      condition_3:e
      condition_n:e
    } -> do_some_thing[label="Yes"]
*********************************************/
  }
}

Giving: