Who knows how to do THIS with an OPT-IN Form?

I'm using an icontact opt-in form. (icontact.com)

People enter name, email, and choose a certain value from a drop down menu.

I would like to alter the code so the page they are redirected to (after opt-in) is different based on the value they choose. For some reason icontact told me they couldn't do this, but it doesn't seem so complex.



Here's the code

<form method=post action="https://app.icontact.com/icp/signup.php" name="icpsignup" id="icpsignup3720" accept-charset="UTF-8" onsubmit="return verifyRequired3720();" >
<input type=hidden name=redirect value="www.LOCATION-AFTER-OPT-IN.com" />
<input type=hidden name=errorredirect value="www.LOCATION-AFTER-ERROR.com" />

<p class="a">
<label>NAME:</label>
<input type=text name="fields_fname">
</p>

<p class="b">
<label>EMAIL:</label>
<input type=text name="fields_email">
</p>

<p class="c">
<label>AMOUNT NEEDED:</label>
<select name="fields_lname">
<option></option>
<option value="5">$500</option>
<option value="6">$600</option>
<option value="7">$700</option>
<option value="8">$800</option>
<option value="9">$900</option>
<option value="10">$1000</option>
<option value="11">$1500</option>
<option value="12">$2000</option>
<option value="13">$2500</option>
<option value="14">$5000</option>
</select>
</p>
<input type=hidden name="listid" value="36210">
<input type=hidden name="specialid:36210" value="GNW1">

<input type=hidden name=clientid value="600030">
<input type=hidden name=formid value="3720">
<input type=hidden name=reallistid value="1">
<input type=hidden name=doubleopt value="0">

<p class="d">
<input type="submit" name="Submit" value="ENTER">
</p>

</form>
<script type="text/javascript">

var icpForm3720 = document.getElementById('icpsignup3720');

if (document.location.protocol === "https:")

icpForm3720.action = "https://app.icontact.com/icp/signup.php";
function verifyRequired3720() {
if (icpForm3720["fields_email"].value == "") {
icpForm3720["fields_email"].focus();
alert("The Email Address field is required.");
return false;
}


return true;
}
</script><BR>



so somehow, I need this to be something like:


If option 5, redirect them _______________
if option 6, redirect them ________________


this way I can customize where people go after opt-in, based on their choice.

Thanks in advance If anyone can throw me a bone!

CW