I have this code and I want made 10 curl connections like this with multi but I don't know how to that with this specific code:
What the code does? 
Make a curl requiest to an .asp page
Uses the result to send some data in a form ($ciudad) then the page get this submit and make an internal request and show an result.
Output the final result of that.
function curl($header,$encoded,$cookie){
  $options = array(
    CURLOPT_USERAGENT       => $_SERVER['HTTP_USER_AGENT'],
    CURLOPT_TIMEOUT         => 120,    
    //CURLOPT_REFERER           => '',
    //CURLOPT_HTTPHEADER        => $header,
    CURLOPT_COOKIE          =>  $cookie,
    CURLOPT_POST            => true,
    CURLOPT_POSTFIELDS      => $encoded,
    CURLOPT_RETURNTRANSFER  => true,     
    CURLOPT_HEADER          => false,    
    CURLOPT_FOLLOWLOCATION  => true,     
  );
  $ch = curl_init("http://procesos.ramajudicial.gov.co/consultaprocesos/consultap.aspx"); 
  curl_setopt_array( $ch, $options );
  $output = curl_exec($ch); 
  curl_close($ch);
  return $output;
}
$cookie = "";
foreach($_COOKIE as $k => $v)
  $cookie .= $k."=".$v.";";
  $cookie = substr($cookie,0,strlen($cookie)-1);
  $encoded = '';
  foreach($_POST as $name => $value) {
    $encoded .= urlencode($name).'='.urlencode($value).'&';
  }
  $lk = "http://procesos.ramajudicial.gov.co/consultaprocesos/";
  $header[] = 'User-Agent: '.$_SERVER['HTTP_USER_AGENT'];
  $header[] = 'Accept: text/xml,application/xml,application/xhtml+xml,text /html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5';
  $header[] = 'Accept-Language: en-us,en;q=0.5'; 
  $header[] = 'Accept-Encoding: gzip,deflate'; 
  $header[] = 'Connection: keep-alive';
  $header[] = 'Cookie : '.$cookie;
  $header[] = 'Content-Type: application/x-www-form-urlencoded';
  $output = curl($header,$encoded,$cookie);
  $CIUDAD = urlencode("Medellin"); // to change
  $CORPORACION = urlencode("JUZGADOS CIVILES MUNICIPALES DE MEDELLIN"); // to change
  $DIGITOS = $numsus; 
  // BEGIN STEP 1
  $__VIEWSTATE = 'id="__VIEWSTATE" value="';
  $i = stripos($output,$__VIEWSTATE) + strlen($__VIEWSTATE);
  $j = stripos($output,'"',$i);
  $__VIEWSTATE = substr($output,$i,$j-$i);
  $__EVENTVALIDATION = 'id="__EVENTVALIDATION" value="';
  $i = stripos($output,$__EVENTVALIDATION) + strlen($__EVENTVALIDATION);
  $j = stripos($output,'"',$i);
  $__EVENTVALIDATION = substr($output,$i,$j-$i);
  $encoded = '__EVENTTARGET=DropDownList1&__EVENTARGUMENT=&__LASTFOCUS=&__VIEWSTATE='.urlencode($__VIEWSTATE).'&__EVENTVALIDATION='.urlencode($__EVENTVALIDATION).'&DropDownList1='.$CIUDAD.'&TextBox13=';
  $output = curl($header,$encoded,$cookie);