some.php

<?php
/**
 * Created by PhpStorm.
 * User: efik
 * Date: 21.11.15
 * Time: 18:47
 */

$container = new ArrayObject();

try {
    $db_1 = new PDO("sqlite:./database_one.sqlite");
    $db_2 = new PDO("sqlite:./database_sec.sqlite");

    $container->offsetSet("db.shop", $db_1);
    $container->offsetSet("db.media", $db_2);

} catch (PDOException $e) {
    unset($db_1);
    unset($db_2);
    throw $e;
}
var_dump($container);

function dumpUsrs(\PDO $pdo)
{

    $data = $pdo->query("SELECT id,name,nick,email FROM users");

    if ($data) {
        return json_encode($data->fetchAll());
    }
    return json_encode("Unable to dump users from");
}

echo dumpUsrs($container["db.shop"]) . PHP_EOL;
echo dumpUsrs($container["db.media"]);