I got it working using your method. On H9-2, RCV CH has to be set to 2 (for H9-2)
XMT CH has to be set to 3 (for H9-3)
RCV.CTL has to be set to NXT.CC#A, LST.CC#B
XMT CC for RING and T+R have to be set to the CC#s on H9-1.
CTL.XMT set to ON,
PGM.XMT has to be turned ON.
OUTPUT has to be set to MERGE.
H9-3 has to be set to:
RCV CH: 3
RV.CTL: NXT.CC#A & LST.CC#B
