<?php

$sql = [['name' => 'Altex'], ['name' => 'ARSIS'], ['name' => 'Avon'], ['name' => 'Azerty'], ['name' => 'BADABUM'], ['name' => 'Boutique Mall'], ['name' => 'Brand Circus'], ['name' => 'CEL.ro'], ['name' => 'ClickShop.ro'],];

$current_letter = null;
foreach ($sql as $row) {
    $name = $row['name'];
    $first_letter = $name[0];
    if ($first_letter != $current_letter) {
        $i = 1;
        if ($current_letter) { // close the previous DIV before starting new one
            echo '</ul>'.PHP_EOL;
            echo '</div>'.PHP_EOL;
        }
        $current_letter = $first_letter;
        echo '<div class="store-wrapper">'.PHP_EOL;
        echo '<div class="store-letter">Store Letter - '. $current_letter .'</div>'.PHP_EOL;
        echo '<ul>'.PHP_EOL;
    }
    if ($i > 3) {
        continue;
    }
    echo "\t<li>".$name.'</li>'.PHP_EOL;
    $i++;
}
if ($current_letter) { // close the last DIV
    echo '</ul>'.PHP_EOL;
    echo '</div>'.PHP_EOL;
}