Use a 12v relay between the trigger and the amps. Many relays have dual outputs that could switch power from a 12v wall wart power supply thus isolating the 861 trigger circuit from the amplifier trigger circuit. A 12v 300ma power supply should be sufficient.

www.cmbintegrations.com
One step from the Presidency
#1 Trinnov Altitude 32-8-16, 271, 8000XE, 7200SEHC, 7200.2, Seaton F18, JL Fathom F113, Revel w990's, Kef R7, ATI 528 Amp, JVC RS4100K, SI screen. Roon Nucleus+, Eno AG, Eno M link, 218.
#2 Mark Levinson No5105, Ayre VX8 and CX8, Vandersteen Treo CT, Preamp varies.
#3 Meridian Ellipse