Hi,
You would have to first create a custom field of the table "order" and of the type "single dropdown" via the menu Display>Custom fields. In the DATA section, you would enter the email addresses in the "value" area and the name of the warehouses in the "title" area.
That way, the customer would be able to select the warehouse during the checkout.
Then, you can customize the emails via the menu System>Emails and add such code at the end of the preload section:
$mail->bcc_email = array($data->cart->xxx);
where xxx is the column name of your custom field. That way, a copy of the email will be sent to the email address selected by the customer.
Note however that since that thread, our solutions have evolved.
Now, with HikaMarket Multivendor, you could configure each warehouse as a vendor and activate the setting to allow the customer to select the vendor during the checkout with the "Allow vendor selector" setting:
www.hikashop.com/support/documentation/1...onfig_market_general
That way, you could do it without any customization.