A method comprises, at a first router configured to perform Bit Index Explicit Replication (BIER) for forwarding of multicast packets in a network, storing configuration information that indicates that the first router belongs to multiple subdomains of a BIER domain, and is able to forward the multicast packets for a virtual private network on the multiple subdomains. The method further comprises, during an auto-discovery procedure, generating an auto-discovery message to include an auto-discovery route and route attributes that indicate the multiple subdomains, and sending the auto-discovery message to a second router of the virtual private network the network.