Hi,
You can edit the view "product / show_quantity" and for the part "show_select" add checks on the product id, or category id in order to have one way or another one of increment.
The if / else must be around the code:
for($j = $min_quantity; $j <= $max_quantity; $j += $min_quantity){
echo '<option value="'.$j.'">'.$j.'</option>';
}
And to chand the increment, you have to edit the 3rd part of the "for" by:
To have something like:
$prodId = hikashop_getCID('product_id');
if($prodId == '1'){
for($j = $min_quantity; $j <= $max_quantity; $j += 1){
echo '<option value="'.$j.'">'.$j.'</option>';
}
}else{
for($j = $min_quantity; $j <= $max_quantity; $j += $min_quantity){
echo '<option value="'.$j.'">'.$j.'</option>';
}
}