MarketPress - Product Additional details added to buyer email

HI. I'd like to be able to add custom instructions on a product by product basis and then have those instructions emailed out to the buyer. This is in the backend for admins to add, not for buyers to provide instructions as this functionality is already available through the Special Instructions Field.

For example - I have a product that I want to send some instructions to the buyer about. On the Create New Product screen I enter all the details of the product and enter the product instructions in a text field. This isn't visible in any product listings or store pages.

Then in the Store Settings -> Messages settings I add in another shortcode for instructions, much like ORDERNOTES for example.

If the order has multiple products it would display all relevant instructions.

Is this possible? Can I add a field to the product creation process?

Any guidance will be greatly appreciated. Thanks!