When all of your cells are connected in a pack of 400-800V connected to a DC fast charger, how do you stop charging the fast cells and continue charging the slower cells?
Separate power factor circuits for each pack, I would think. With everything switching over to GaN now and bringing the prices down that should be doable.
I would expect you could only do it with the onboard charger and only if it has one charger per module or the ability to connect the singular charger to each module.