XSL Positional Grouping Problem

Hello, I'm hoping that someone can point me in the right direction.  I
have the following need:

I have been sent an MS Excel file that I have been asked to transform
in the following way...

<Table>
 <Row>
   <Cell><Data>Level 1</Data></Cell>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
  </Row>
<Row>
   <Cell/>
   <Cell><Data>Level 2</Data></Cell>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
   <Cell/>
  </Row>

<Table>
 <Level><Data>Level 1</Data>
     <Level><Data>Level 2</Data</Level>

 </Level>
</Table>