title: Finding the multicast IP that a datagram was sent to
body: <p>In my application I have one MulticastSocket that joins 40 multicast IP addresses (On the same port).</p>
  
  <p>When receiving a datagram, is there a way to find the specific Multicast IP that a it was sent to ?</p>
  
  <p>The same question about the new "DatagramChannel" (in Java 7), that also support multicasting.</p>
  
  <p>Thank you very much !</p>