In some message-board communities on-line a relay can also be a reference to a game such as a use of the infamous 'Word Association'. It's also used to refer to a fictional story written by multiple writers who take it in turns to add their own chapter; typically concentrating on their own specific character.
2. Story relay.
The authors have control over ALL the characters as well as the power to direct the flow of the plot.
"Yeah. I can't believe he killed off the emporor."