Meta Box Tabs and Group together

tabs-group.php

<?php
add_filter( 'rwmb_meta_boxes', 'prefix_register_meta_boxes' );

function prefix_register_meta_boxes( $meta_boxes )
{
	$prefix = 'your_prefix_';

	// 1st meta box
	$meta_boxes[] = array(
		'title'  => __( 'Books', 'rwmb' ),
		'pages' => array( 'post' ),
		'tabs'   => array(
			'media'  => 'Media Item',
			'author' => 'Author',
		),

		'fields' => array(
			array(
				'id'     => 'chapters',
				'tab'     => 'media',
				'name'   => __( 'Chapters', 'rwmb' ),
				'type'   => 'group', // Group type
				'clone'  => true,    // Can be cloned?

				// List of child fields
				'fields' => array(
					array(
						'name'    => __( 'Chapter Title', 'rwmb' ),
						'id'      => 'chapter_title',
						'type'    => 'text',
						'columns' => 6, // Display child field in grid columns
					),
					array(
						'name'    => __( 'Page', 'rwmb' ),
						'id'      => 'page',
						'type'    => 'number',
						'size'    => 5,
						'columns' => 6, // Display child field in grid columns
					),
				),
			),
			array(
				'id'     => 'author',
				'tab'     => 'author',
				'name'   => __( 'Authors', 'rwmb' ),
				'type'   => 'group', // Group type
				'clone'  => true,    // Can be cloned?

				// List of child fields
				'fields' => array(
					array(
						'name'    => __( 'Name', 'rwmb' ),
						'id'      => 'name',
						'type'    => 'text',
						'columns' => 6, // Display child field in grid columns
					),
					array(
						'name'    => __( 'Email', 'rwmb' ),
						'id'      => 'email',
						'type'    => 'text',
						'size'    => 5,
						'columns' => 6, // Display child field in grid columns
					),
				),
			),
		),
	);
	return $meta_boxes;
}