gform pre render and cookies

I am trying to make an email route based on whether a cookie is satisfied. However, it's harder than I thought. What trick am I missing? Here's what I have:

cookie is $_COOKIE["src"] and will have nothing if not triggered. To route the email I know that I need a selection enabled to use as conditional logic. I want to create this selection field and CSS it as display:none.

I have been able to get the right code except here the function does not know that the cookie is set:

if($_COOKIE["src"]){
$items[] = array("value" => "gsm", "text" => "gsm");
} else {
$items[] = array("value" => "", "text" => "");
}

this is the entire code:

function my_custom_population_function($form){
$items = array();
if($_COOKIE["src"]){
$items[] = array("value" => "gsm", "text" => "gsm");
} else {
$items[] = array("value" => "", "text" => "");
}
foreach($form["fields"] as &$field)
if($field["id"] == 8){
$field["choices"] = $items;
}
return $form;
}

also, i will want to share this amongst all forms but the input number will not always be 8. any way around duplicate code?

there's definitely a record of the cookie as i can generate it via this line:

$items[] = array("value" => "gsm", "text" => "gsm");

I can use jQuery to output the value with this code fine:

<?php if($_COOKIE["src"]){ ?>
<script type="text/javascript">
var src = <?php echo $_COOKIE["src"];?>;
</script><?php } ?>

<script type="text/javascript">if(src){document.write(src);}</script>

tried it to no avail :(

nobody know how to do this?

Ignore my comment above... It looks like you need to set the domain on the cookie...
setcookie("test", 1, time()+3600, "/", str_replace('http://www','',get_bloginfo('url')) );