Marcus said in a Facebook post:
After launching the existing person-to-person payment solution in Messenger two years ago, we’re very glad to bring you group payments starting today. Splitting the bill, concert tickets, a present for a friend, lodging for a trip or whatever needs to be settled in a group is now easier than ever. And you can do it right in the very place you’re already using to make group plans.
UPDATED: Product manager for consumer payments Partha Sundaram shared a guide to the new feature in a Newsroom post:
Simply tap on the plus sign in the bottom-left-hand corner of a group conversation to find more features, and tap the payments icon ($). Then choose who to send or request money from. You can choose everyone in the group or only a few members. Enter the amount you want to request per person or the total sum to divide evenly, either including yourself in the calculation or not. Finally, you can specify what the money is for—maybe a pizza party, teacher gift or more. Once you’re ready, tap request.
To make it super simple to keep track of everything, a message will appear in the group conversation showing who has paid. At any time, you can also view the request details in full-screen. Coordinating group payments has never been easier.