different admin email per product

hi,
I see your customization feature of emails in the configuration. Hope you can help me with this:

Customers buy product "x hours thesishelp from one of my teachers", I want an email sent to me AND the teacher after succesful order of the product. How can I make this happen, I receive email as admin/owner: yes. But how can I add an automatic notification email to the specific teacher?
I guess I need to make a hidden extra field with the product: the emailaddress of the teacher. And then to include a PHP statement to fetch that email in the Configuration/emails/Order administrator notification.
Would you be able to write some php for this?

Thank you,
Damiaan

hi Nicolas,
sounds like a brilliant solution, will try it out the next days, thank you!
Damiaan

hi, how do I combine the two advices in this thread?

//this is to send multiple emails//
<?php $data->customer->user_email = array($data->customer->user_email,'email2@mywebsite.com','email3@mywebsite.com'); ?>

//this to do that dynamically based on a custom field at the product page (different email per product)
$class = hikashop_get('class.product');
$prod = $class->get($item->product_id);
$data->customer->user_email[]=$prod->contact_email;

I tried putting the second in the array() - but that got me into troubles, thank you!