JSFiddle - React, Tailwind, and code Playground

HTML

<table>
  <table style="width:100%">
  <tr>
    <td>A</td>
    <td>B</td> 
    <td>C</td>
  </tr>
  <tr>
    <td rowspan=2>1</td>
    <td rowspan=2>2</td>
     <td>sub C 1</td>
  </tr>
  <tr>
    <td>sub C 2</td> 
  </tr>
  <tr>
    <td>3</td>
    <td>4</td>
    <td>5</td>
  </tr>
  <tr>
    <td>6</td>
    <td>7</td>
    <td>8</td>
  </tr>
</table>

CSS

td {
    border:solid;
    width: 30px;
    height: 30px;
}

table tr:nth-child(2n) {
      background-color: #F8ECE0; }

JavaScript

$( "<tr style='display:none'></tr>" ).insertAfter('tbody tr:has(td[rowspan])');