After the introduction of payment from person to person through Messenger, in 2015, Facebook extends the possibility of payments for each member of a Messenger group.
Payment is made by pressing the payment button (dollar sign) in the group. The system is useful where the group has to pay a bill (from each member to a member of the group) or vice versa, when a group member sends money request to all other members.
The total amount is divided equally to members, including or not the member that is requesting payment. Payment notification can add explanations.
The service is offered by Facebook for free. This way, Facebook joins the other messaging applications that already support online payments, like Snapchat.
Facebook is considering a further expansion of online payments for WhatsApp.
For now, this payment system is only available to US on desktop computers and mobile devices with Android.