Typing multicast addresses is not very fun... that's why you need a channel information service ! VideoLAN has implemented a channel information service based on the SAP/SDP standard. The SAP announces about the multicast programs are sent on the network (via the multicast address 220.127.116.11 reserved for this purpose). On the client side, VLCs receive these annouces and automatically add the programs announced to their playlist.
VLC can send the SAP announces associated with the programs it is streaming. VLS can't do that, but an independant program, the mini-SAP-server, can send the announces for the programs sent by VLS.