ciao!

partendo dal tuo spunto sono riuscito a risolvere:
Codice PHP:
<?php
$alphas 
range('A''Z');
$array = [];
foreach (
$objsBrands as $r) {
    
$key substr($r['brand_nome'], 01);
    
$array[$key][] = $r['brand_nome'];
}
?>
<div class="row">
    <div class="col-sm-12">
        <div class="row">
            <?php
            
foreach ($alphas as $a):
                foreach (
$array as $key => $val):
                    if (
$key == $a):
                        
?>
                        <div class="col-sm-2">
                            <h4 class="page-header">
                                <?php echo $a?>
                            </h4>
                            <ul>
                                <?php foreach ($val as $v): ?>
                                    <li><?php echo $v '<br>'?></li>
                                <?php endforeach; ?>
                            </ul>
                        </div>
                        <?php
                    
endif;
                endforeach;
            endforeach;
            
?>
        </div>
    </div>
</div>
mi sembra funzionare correttamente!
grazie per l'aiuto!