Nested array objects for child jobs

Hi everyone, I ran into a problem with getting a reference out of an object in an array for a placeholder in a child job.

I'm using the Generic extractor for Zenhub API. I get the following response:

{
  "pipelines": [
    {
      "id": "595d430add03f01d32460080",
      "name": "New Issues",
      "issues": [
        {
          "issue_number": 279,
          "estimate": { "value": 40 },
          "position": 0,
          "is_epic": true
        },
        {
          "issue_number": 142,
          "is_epic": false
        }
      ]
    },
    {
      "id": "595d430add03f01d32460081",
      "name": "Backlog",
      "issues": [
        {
          "issue_number": 303,
          "estimate": { "value": 40 },
          "position": 3,
          "is_epic": false
        }
      ]
    },
    {
      "id": "595d430add03f01d32460082",
      "name": "To Do",
      "issues": [
        {
          "issue_number": 380,
          "estimate": { "value": 1 },
          "position": 0,
          "is_epic": true
        },
        {
          "issue_number": 284,
          "position": 2,
          "is_epic": false
        },
        {
          "issue_number": 329,
          "estimate": { "value": 8 },
          "position": 7,
          "is_epic": false
        }
      ]
    }
  ]
}

I need to use the "issue_number" for a child job, to retrieve more data about the individual issues. But I cannot get it to work for all pipelines. If I only pick the first pipeline, it works:

{
    "endpoint": "/p2/workspaces/{1:workspace}/repositories/{1:repoid}/board",
    "dataType": "board",
    "dataField": "pipelines.0.issues",
    "placeholders": {
    "1:repoid": "repoid",
    "1:workspace": "id"
    },
    "children": [
    {
        "endpoint": "/p1/repositories/{2:repoid}/issues/{1:issue_number}/events",
        "dataType": "issuesEvents",
        "dataField": ".",
        "placeholders": {
        "2:repoid": "repoid",
        "1:issue_number": "issues.issue_number"
        }
    }
    ]
}

But is there to make it work for all pipelines? That is for each pipeline get all issues. It seems similar to this example from the docs, just the value is a object and I need to retrieve the value from it.

Thanks for help!