Enable Billing document to send mails to multiple Customer email addresses using BRF+ ?

I've configured Billing document message output with the channel as EMAIL communication using BRF+.

I have a requirement to send out an invoice to multiple email addresses based on the customer number. For example, a customer has multiple email IDs maintained. Currently, the invoice is being sent to one email ID only.

What is the configuration needed to enable invoice to be sent automatically to multiple recipients dynamically ?