Are you running single restaurant or multi restaurant?
If single restaurant you can set an admin email and location email to the addresses you want to receive notifications at and then in System -> Settings ->Mail -> Order Confirmation/Alert Email choose the 'To admin' and 'To location' options.
This is a bit hacky but will allow you to send to two addresses.
The other option is to disable the input validation/verification for email inputs in the admin area, specifically at Restaurant -> Locations. Then enter the location email in the format of;
email@example.com, firstname.lastname@example.org, email@example.com
As I suspect putting a comma between the addresses will achieve what you need, if the character were allowed in the email field.