Whenever I need to do somthing like this I create indexed elements and process from there (I'm assuming you don't want multi-select drop down since you are presenting the same set of options twice) .

Example HTML

<input type="hidden" name="num_of_options" value="2">
<select name="select1">
  <option name="foo">Foo</option>
  <option name="bar">Bar</option>
</select>
<select name="select2">
  <option name="foo">Foo</option>
  <option name="bar">Bar</option>
</select>
[download]

This makes reading the values from CGI, trival and can be set up easily with a template.