Don’t display bottom border on cells in split rows

[liZe]

<style>
  @page { margin: 0; size: 10em 4em }
  body { margin: 0 }
  td { border-bottom: 1px solid }
</style>
<table>
  <tr>
    <td>
      a
    </td>
    <td>
      a<br>
      a<br>
      a<br>
      a
    </td>
  </tr>
</table>