acf-fontawesome-add-settings-group.php

<?php
add_action('acf/render_field_group_settings', 'hwk_acf_field_groups_add_settings_fa', 10);
function hwk_acf_field_groups_add_settings_fa($group){
    // Font Awesome
    // Return: "hwk_fontawesome": "fa-500px"
    acf_render_field_wrap(array(
        'label'             => __('Font Awesome','acf'),
        'instructions'      => __('Instructions','acf'),
        'type'              => 'font-awesome',
        'name'              => 'hwk_fontawesome',
        'prefix'            => 'acf_field_group',
        'value'             => (isset($group['hwk_fontawesome'])) ? $group['hwk_fontawesome'] : '',
        'allow_null'        => true, // true | false
        'show_preview'      => false // true | false
    ));
}