Bill,
I don't know about the Tyros but the PSR2000 has in the Midi function settings a "chain play" which will just go down all of the songs in a row and continuously play them. When it gets to the end I believe it starts again at the top. It can be what is programmed or on a floppy.
Check under SONG/Selection/Selection Control I/II/III/IV/V/VI
(Chain, Random and Next reservation are available.)
- Brian