I think this is new - I'm so pleased with it I just had to share!
Study this image and all will be revealed...
The four tracks containing the different takes are set to sends only and the sends (not shown) are set to zero.
Track 5 contains the Comping Rack - it's a MIDI track so you can easily crate an empty clip of any length and use the clip envelope to control the chain selector - alternatively in arrange view you could use automation.
Each chain in the rack contains a compressor, but it is not used as such. It is used purely because it has the ability to monitor the sidechain input. changes to the compression parameters have no effect on the sidechain sound - except for the FB button which mutes it.
Each compressor takes its sidechain input from a different "Take" track
Setup the chain selector something like in the image - the fade-in/out on each range is necessary, it doesn't work without them.
Click on the chain selectors numeric scale to make the selector jump between regions and select a particular take.
Automate it and bob's your uncle.