I'm working on a program to move things between layouts, and while there's a way to go yet, the first part I've done is useful for copying large numbers of objects from one track to another in situ.
Consider this a beta of an experiment, and adjust your expectations accordingly... proper docs will follow the finished program, which I'm working on here and there
Quick guide: Load the old track, select the objects, click 'add selection', repeat until you have all your objects selected. The 'S' and 'H' buttons will show you a subgroup as a selection or in-hand respectively. Load the new track and you can now place each subgroup manually by using the 'H' button and the 'O' key, or, if the objects are going into the exact same place as they've come from, you can use the 'place all' button to place them all in one go.
(Load/Save don't work yet, and there's no confirmation when you hit the 'Clear' button, so be careful
Those functions and some more options for placement are in the works)