A disclosed method is performed at a first boundary node bordering a BIER domain. The method includes receiving a message associated with a source and group for multicast from outside the BIER domain. The method further includes generating an encapsulated message based on the message, a metric, and a first proxy address of the first boundary node. The method also includes forwarding the encapsulated message through the BIER domain to at least one second boundary node bordering the BIER domain and connectable to the first boundary node. The first boundary node additionally triggers the at least one second boundary node to decapsulate the encapsulated message for forwarding out of the first domain and store a record including the source, the group, the metric representing the cost of the first boundary node to the source, and the first proxy address on the at least one second boundary node.