How to chain four conditions in a shorthand if-else-statement

I am displaying a Google map on my website which loops through a number of values based on their co-ordinates in the database.

There are four different types of partners and these are highlighted with different coloured marker pins.

So far I am successfully showing 3 different coloured markers using a shorthand if-else statement. How can I add one more condition in to this to show my final coloured marker for Type4?

<?php
$markers = array();
foreach ($current as $key => $value) {

$markers[] = array(
  'latLng' => array($value['Partner']['lat'], $value['Partner']['lon']),
  'options' => array(
    'icon' => $this->Html->url('/img/icons/'.($value['Partner']['type1'] ? 'pink-pin.png' : ($value['Partner']['type2'] ? 'green-pin.png' : 'purple-pin.png'))),
  ),
  'data' => array(
    'html' => 
      '<p>'.$value['Partner']['name'].'</p>'
  ),
);
}
?>