Refer to the exhibit. The service provider has deployed segment routing in its core. P2 connects to P3 and P4 through a point-to-multipoint link, as shown. The service provider supplies connectivity for a large enterprise with three primary offices in different geographic regions. Each office connects through one of the three PEs. The enterprise wants to implement multicast traffic across the service provider to stream mission-critical applications among sites. The applications are sourced from a server connected to the network through PE2. Which action must the network-engineering team take so that multicast traffic flows between the enterprise sites over the point-to-multipoint link?