Firefox search plugin: varying result destination URL based on results returned?

Question

I want to create a firefox search plugin with an autocomplete function. However I have a twist to the standard, "return a result and append to the URL" method. Depending on the result returned in the autocomplete how do I use a different "template URL" (or destination URL) when the user submits the search? Can you return a result and a destination URL for that result? Or can you return a result variable and another variable to go into the URL?

<Url type="application/x-suggestions+json" method="GET" template="http://suggestqueries.google.com/complete/search?output=firefox&amp;amp;client=firefox&amp;amp;qu={searchTerms}"/&gt;
<Url type="text/html" method="POST" template="<THIS URL NEEDS TO VARY BASED ON RETURNED RESULT>">
  <Param name="order" value="{searchTerms}"/>

</Url>
<SearchForm>http://www.google.com/firefox&lt;/SearchForm&gt;
</SearchPlugin>