I believe Black Box makes a composite video splitter, and so does these guys:

http://www.commspecial.com/videosplt.htm

Most if not all DVD players have composite video out, and this should work.
With the one in the link above, you'd need 2 units, since it only has 6 video
outputs.

Do a search wth Google and you can find more. Just search under Composite
Video Splitters.

Raymond