Krell MAT

Hi. I need some input who knows some or more details about Krell's Multi-Amp Throughput(TM). Can it be applicable for any power amp to DIY implement? How it's been achieved? Is it being buffered through the input differential stage? Otherwise how it's being different from just Y-connecting 2 or more amps? Pro amps such as Crown, QSC have balanced throughput which helps to easily connect them if double-power needed and also makes it easy to integrate with active x-over.
Just collecting some technical tips and tricks