This was implemented in 5.0.x 
, we are now on 5.1.1 on WIFI and awaiting 5.2.x beta to be ready.
To turn this on, go to the device settings menu under Behavior and enable Auto Song Part Change (6x6), this will set the Aeros to automatically transition to the selected next part like 2x2 works. To keep changing which part you want to switch to, keep tapping the next part button to toggle the selection and change the transition destination. This works better if the Change Part behavior setting is set to End of Loop.