I am not sure what you mean by an in Tandem story, but I am a member of a radio forum in RSA and we have a posting where members all get to write a story by adding their sentence to follow on from where the last member left off. The end result was hilarious to read. This brought a lot of would be writers out of the closet as well.

Copyright S.R. Hulley
Chin up, stay strong! Hugs!