Ability to send invoice to internal employees

We have a company that requires extra information to be added to the invoices before being sent over to them. This works when we add an employee to the company and use an internal email, however, this would need to be done each time if more companies needed the extra information added prior to sending the invoices to them.

The request is to find a way to make it in the future where invoices can be sent to internal employees as well as employees at the company.