Advanced Custom Fields Repeater With 2 Loops

I am setting up a photo gallery, with a main image and 6 thumbnails under it. Upon hovering the thumbnail, the main image will change. Simple stuff. The problem I am having is that when the page loads, the main image is the image from the first repeater row (like I want), but then in the thumbnails, the first repeater row doesn't get output. So only thumbnails 2 - 6 are being output. I am new to Advanced Custom Fields. Not sure if it's something to do with that or if it's just a simple PHP error. Here is my code:

<?php if( have_rows('property_images') ): 

    while( have_rows('property_images') ): the_row();

        $image = get_sub_field('property_image');
        $url = $image['url'];

    ?>

    <img src="<?php echo $url ?>" class="property-main-img">

    <?php
        break;
        endwhile;
        endif; 
    ?>

            <ul>

                <?php if( have_rows('property_images') ): 

                        $i = 1;

                        while( have_rows('property_images') ): the_row();

                            $image = get_sub_field('property_image');
                            $url = $image['url'];

                        ?>

                        <?php if($i % 3 == 0) { ?>

                            <li class="prop-thumb-r"><img src="<?php echo $url ?>" alt="<?php echo $image['alt']; ?>" width="170" /></li>

                        <?php } else if($i == 1 || $i % 4 == 0) { ?>

                            <li class="prop-thumb-l"><img src="<?php echo $url ?>" alt="<?php echo $image['alt']; ?>" width="170" /></li>

                        <?php } else { ?>

                            <li><img src="<?php echo $url ?>" alt="<?php echo $image['alt']; ?>" width="170" /></li>

                        <?php } ?>

                        <?php
                             $i++;
                         endwhile; 
                    endif; 
                ?>

            </ul>