Systems and methods are provided for use in processing transactions to payment accounts by transacting users, based on authentication of designated users associated with the payment accounts. One exemplary method includes receiving, at a computing device, a message associated with a transaction to a payment account where the transaction is initiated by a first user, and retrieving an authorization profile for the payment account based on a primary account number for the payment account. The authorization profile includes an indication of a communication device associated with a second, designated user also associated with the payment account. The method also includes soliciting, by the computing device, from the first user, a selection of the communication device and then, in response, transmitting an authentication request for the transaction to the second user at the communication device, thereby permitting the second user to grant permission for the transaction to the payment account.