What happens if there are multiple contacts for a bill-to

We have a situation where there are multiple contacts for a customer bill-to with dunning role. Invoice gets sent to the contact based on the bill_to_contact_id on the customer trx table. When it comes to sending dunning letters, the fulfillment workflow is randomly picking the 1st contact on the list at bill-to if there are more than one contact there by sending the dunning letter to a different person who received the invoice.

My questions here is, is there a way we can send the e-reminder/dunning letters to the same bill_to_contact_id ?

Appreciate your help and let me know if I am missing something