If you need to connect to more than one database simultaneously you can do so as follows:
$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);
Note: Change the words “group_one” and “group_two” to the specific group names you are connecting to (or you can pass the connection values as indicated above).
By setting the second parameter to TRUE (boolean) the function will return the database object.
Visit https://www.codeigniter.com/userguide3/database/connecting.html for further information.