Hi,
here my sample..
My template like this

<select>
<tmpl_loop loop_one>
<option name='<tmpl_var name>'> <tmpl_var value> </option> 
      <tmpl_if loop_two>
      <tmpl_loop loop_two>
 <option name='<tmpl_var name_one>'> <tmpl_var value_one>  </option>
      </tmpl_loop>
       </tmpl_if>
</tmpl_loop>
</select>
[download]

My prg is like this

my (@loop_two,@loop_one);

for(@arr_name) {
   push @loop_two, {
                      name_one => 1,
                      value_one => 2 
                   };

}

for(@arr_one) {
   push @loop_one, {
                     name => 1,
               value => 2,
             loop_two => \@loop_two 
                   };
}

$html->param(loop_one => \@loop_one);

return $html->output();

where $html is HTML::Template object.
[download]

-kulls