Hide Gallery from the_conent

Question

I'm using a function to separate Featured Content.

What I mean is that: if I selected format Gallery will show the First Gallery in my post , if I choose format Video , will show a video instead .

this is the function:

//Get Featured Media depending on Format
if (!function_exists('get_featured_media')):
    function get_featured_media()
    {
        global $post, $prefix;
        $image = get_the_post_thumbnail($post->ID, 'dreams-640x360', array('class' => "lazyload"));
        $image_caption = esc_html(get_the_post_thumbnail_caption());

        $gallery = get_post_gallery($post->ID, false);
        //$gallery_img_caption = esc_html(the_title());

        $video = get_post_meta($post->ID, "{$prefix}videos_oembed", true);
        $oembed_code = wp_oembed_get($video);

        $getMedia = '';



        if (has_post_format('gallery')) {

            if (get_post_gallery()) {

                $getMedia .= "<figure class=\"f4_article-info__meta--gallery\">";

                foreach ($gallery['src'] as $src) {
                    $getMedia .= "<img src=\"$src\" class=\"my-custom-class\" alt=\"$gallery_img_caption\" />";
                }
            } else {
                if (has_post_thumbnail($post->ID)) {
                    $getMedia .= "<figure class=\"f4_article-info__meta--gallery\">";
                    $getMedia .= "$image";
                    $getMedia .= "$image_caption";
                }
            }

        } elseif (has_post_format('video')) {

            if ($video) {
                $getMedia .= "<figure class=\"f4_article-info__meta--video\">";
                $getMedia .= "$oembed_code";
            } else {
                if (has_post_thumbnail($post->ID)) {
                    $getMedia .= "<figure class=\"f4_article-info__meta--video\">";
                    $getMedia .= "$image";
                    $getMedia .= "$image_caption";
                }
            }

        } else {
            if (has_post_thumbnail($post->ID)) {
                $getMedia .= "<figure class=\"f4_article-info__meta--image\">";
                $getMedia .= "$image";
                $getMedia .= "$image_caption";
            }
        }

        if (!empty($getMedia)) {
            $getMedia = "\n<!-- Featured Media -->\n" . $getMedia . "\n</figure>";
            echo $getMedia;
        }

    }
endif;

Now Format Gallery will work using the first gallery created in our post.

With this idea , I would like to hide the first gallery inside the_content()

The obvious approach is to hide it via CSS (http://codepen.io/DreamsEngine/pen/BpPLXg) , but that that will be rendered by DOM isn't ? , and what everyone is looking is performance...

What do you recommend for this?