Behringer's auto-on feature works poorly with all but the largest signals and is useless in my opinion.
Check out the Teensy Encoder project at:
viewtopic.php?f=15&t=17221#p129055This encoder can activate relays for the Behringer's power when Hauptwerk sends the Organ Ready signal.
I'm currently using a Raspberry Pi wireless connection to a Furman power conditioner which has been modified to include a Pi Zero W ($10) driving four relays. The relays can be controlled individually or in a sequence from another Raspberry Pi or other computer.
I use a 40A solid state relay (SSR) sold by Sparkfun (again $10) that can be activated by a wide range of DC voltages from 3 to 32v. It goes without saying that any power relays are installed in electrical enclosures and wired safely and in compliance with any electrical codes. It's good to mount the SSRs to a metal surface or even a proper heat sink if operating above just an amp or two.