i found this in a diff post but couldn't get it to work though...
timedemo 1
set loop1 "demo demo001;wait;set nextdemo vstr loop2"
set loop2 "demo demo002;wait;set nextdemo vstr loop1"
vstr loop1
put that into a "<name>.cfg" then you can just type "exec <name>.cfg" in the console to loop the 2 demos.
although as i said i haven't got this to work but i also haven't really tried to mess w/ it much.