JSFiddle - React, Tailwind, and code Playground

HTML

<table id="groupTable"></table>

CSS

table td { border: 1px solid black; padding: 10px; }

JavaScript

var data = {
  "set": [
    {
      "id": 1,
      "segment_desc": "Segment 1",
      "segment_summary": [
        {
          "section_type": "domain group",
          "section_value": "group 1",
          "children": [
            {
              "children": [
                {
                  "format": "float",
                  "measure": "users clicking",
                  "value": 340
                },
                {
                  "format": "float",
                  "measure": "% users opening",
                  "value": 10
                }
              ],
              "section_type": "vertical",
              "section_value": "all"
            },
            {
              "children": [
                {
                  "format": "float",
                  "measure": "users clicking",
                  "value": 340
                },
                {
                  "format": "float",
                  "measure": "% users opening",
                  "value": 10
                }
              ],
              "section_type": "vertical",
              "section_value": "cars"
            }
          ]
        }
      ]
    },
    {
      "id": 2,
      "segment_desc": "Segment 2",
      "segment_summary": [
        {
          "section_type": "domain group",
          "section_value": "group 2",
          "children": [
            {
              "children": [
                {
                  "format": "float",
                  "measure": "users clicking",
                  "value": 340
                },
                {
                  "format": "float",
                  "measure": "% users opening",
                  "value": 1.24
                }
              ],
              "section_type": "vertical",
              "section_value": "all"
            },
            {
              "children": [
                {
                  "format": "float",
                  "measure": "users clicking",
                  "value":...