bp_register_group_extension( string $group_extension_class = '' )

function bp_register_group_extension( $group_extension_class = '' ) {

	if ( ! class_exists( $group_extension_class ) ) {
		return false;
	}

	// Register the group extension on the bp_init action so we have access
	// to all plugins.
	add_action( 'bp_init', function() use ( $group_extension_class ) {
		$extension = new $group_extension_class;
		add_action( 'bp_actions', array( &$extension, '_register' ), 8 );
		add_action( 'admin_init', array( &$extension, '_register' ) );
	}, 11 );
}