php how to connect multiple remote database in codeigniter

Question

I tried the code below to connect to multiple remote databases in CodeIgniter. I am only able to connect to 1 remote database, but can't connect to two more. How can I do that?

class CI_DB_driver {

        var $username       ='admin';
        var $password       ='********';
        var $hostname       ='s1607';
        var $database       ='habitat';
        var $dbdriver       = 'mysqli';
        var $dbprefix       = '';
        var $char_set       = 'utf8';
        var $dbcollat       = 'utf8_general_ci';
        var $autoinit       = TRUE; // Whether to automatically initialize the DB
        var $swap_pre       = '';
        var $port       = '';
        var $pconnect       = FALSE;
        var $conn_id        = FALSE;
        var $result_id      = FALSE;
        var $db_debug       = FALSE;
        var $benchmark      = 0;
        var $query_count    = 0;
        var $bind_marker    = '?';
        var $save_queries   = TRUE;
        var $queries        = array();
        var $query_times    = array();
        var $data_cache     = array();
        var $trans_enabled  = TRUE;
        var $trans_strict   = TRUE;
        var $_trans_depth   = 0;
        var $_trans_status  = TRUE; // Used with transactions to determine if a rollback should occur
        var $cache_on       = FALSE;
        var $cachedir       = '';
        var $cache_autodel  = FALSE;
        var $CACHE; // The cache class object

        // Private variables
        var $_protect_identifiers   = TRUE;
        var $_reserved_identifiers  = array('*'); // Identifiers that should NOT be escaped

        // These are use with Oracle
        var $stmt_id;
        var $curs_id;
        var $limit_used;