adding non-data controls in nested silverlight datagrid

Question

I am using nested silverlight datagrid. I am using RowdetailsTemplate to show 2nd level of datagrid. Once all the data in 2nd level of datagrid is shown, I want to add a stackpanel at bottom each row in second grid. This stackpanel will have some controls in it. Is there anyway I can acheive this?

<datagrid1>
  <row1>
    <datagrid2>
       <row1>
       <row2>
       <row3>
      <stackpanel>
    </datgrid2>   
  </row1>
  <row2>
    <datagrid2>
       <row1>
       <row2>
       <row3>
      <stackpanel>
    </datgrid2>   
  </row2>
</datgrid1>