I think maybe what you're asking for is two tables within a table? It would look like two tables next to each other. The code below produces one big cell in each table, but you can add in more rows and cells as needed.

<table> <!-- mommy table -->
<table> <!-- left child -->
<tr>
<td>Here's table detail for left child.</td>
</tr>
</table> <!-- end left child -->
<table> <!-- right child -->
<tr>
<td>Here's table detail for right child.</td>
</tr>
</table> <!-- end right child -->
</table> <!-- end mommy -->

Lisa