perch_blog_custom - Filtering by multiple sections

Hi! I've got an array for a blog split out by sections. The code:

<?php  
                    perch_blog_custom(array(
                    'count' => 4,
                    'template' => 'news-feature-slider-4.html',
                    'sort' => 'postDateTime',
                    'section' => 'news',
                    'sort-order' => 'DESC',
                    ));
                    ?>

It seems that the 'section' filter can only be used for ONE section. How to I mix in more sections to filter the 4 slots? Tried a comma but that broke it.