Why don't you do what I do? My main story is called Little Cherine. Where I need to diverge to examine 'side' stories or characters, I call those Little Cherine Satellite Stories (with its own title, like 'The Boxee'). I also note that it is taken from LC Book 11. That way I can determine how much it interacts with the main story, if at all, apart from originating from it. It also leaves me free to integrate the characters and give them an appearance later on (the Boxee characters, thanks to me the author - and the pleading of everyone in the main story, are made a part of the Syncosmi and go on many adventures with the main family throughout a number of books).