Form Redirect Based on 2 Variables

We would like to use 3 different thank you pages based upon the radio buttons that people select for cars and trucks. The current script was created for only cars and works perfectly. Feel free to use if anyone wants a script that works in this instance.

<script>
$("input[name='cars']:checked").live('change', function() {
  switch ($(this).val()) {
    case '7 or less':
        window.module.lp.form.data.url = "URL1";
        break;
    case '8 or more':
        window.module.lp.form.data.url = "URL2";
        break;
	}
});
</script>

Now we need to add trucks with either “4 or less” or “5 or more” as the options. Here are the possibilities:

Cars 7 or less & Trucks 4 or less: URL1
Cars 7 or less & Trucks 5 or more: URL2
Cars 8 or more: URL3 (same as adding Trucks 4 or less OR Trucks 5 or more)

Does anyone know how to update the existing code to include 2 variables with 3 different thank you pages?