All things related to multicast

Hi,

>    especially internationally. The data streams are all files and any packet
>    loss would cause a file to become corrupted and unusable.

that pretty much cancels out multicast (especially across the internet). 

as others have said, methods such as BitTorrent are very efficient at shipping
that volume of data around . protection of data by using shared GPG/PGP key
would allow transit.  

regarding particular streams, whilst the Torrent method is efficient, you may 
need
to write your own program that utilizes the technology but also does the
subscribe/access.

alan