Meta Box

Meta Box: 4.5.6
Conditional Logic: 1.0.7

Code:

// Projects
	$prefix = 'projects_';
	$projects_divisions = get_terms( 'projects_division', array( 'hide_empty' => 0 ) );
	$projects_categories = get_terms( 'projects_category', array( 'hide_empty' => 0 ) );
	$projects_categories_list = array();
	$projects_division_cats_options = array();
	
	// Get and store categories
	foreach ($projects_categories as $category) {
		$projects_categories_list[$category->slug] = $category->name;
	}
	
	// Create divisions and categories options
	foreach ($projects_divisions as $division) {
		$name = $division->name;
		$slug = $division->slug;
		
		$projects_division_cats_options[] = array(
		   'name' => __( '', $prefix ),
			'id' => $prefix . $slug,
			'type' => 'checkbox_list', // List used instead of single (preferred styling)
			'options' => array(
				1 => __( $name, $prefix ),
			)
		);
		
		$projects_division_cats_options[] = array(
		   'name' => __( '<div style="width:7px; margin-top:-4px; border-right:1px solid #aaa;">&nbsp;</div>', $prefix ),
			'id' => $prefix . $slug . '_categories',
			'type' => 'checkbox_list',
			'options' => $projects_categories_list,
			'hidden' => array($prefix . $slug, 0),
			'after' => '<div style="border-top:1px solid #ededed; height:7px;" />&nbsp;</div>',
		);
	}
	
	// Divisions and Categories
    $meta_boxes[] = array(
		'id' => $prefix.'divisions_categories',
        'title' => 'Divisions & Categories',
        'pages' => array( 'projects' ),
		'context' => 'side',
        'priority' => 'low',
        'fields' => $projects_division_cats_options,
    );