I´ve searched aescripts, the forum here, mograph.net and via google, but couldn´t find anything about this topic. Maybe you know a script, with which you can automatically copy a layer from the middle of one composition to the start of another composition? Right now, if the "target"-composition is too short, the copied layer won´t show up in the timeline, so you can grab it to the start...
We offer custom scripting services and can create this script for you, please open a support ticket and if possible provide a screencast showing the behavior you are looking for so that it's clear.