Is this still a problem? I have almost the same setup as yourself successfully wired in a home run topology. I briefly had an issue with comms but setting the G61RSLto non-controller in the configuration program and holding down clear to make the centre master speaker the controller solved that.

Let me know if you need any help and I can always send you my configuration if needs be. I know that you are trying to make the G61 the controller as opposed to a speaker so maybe that is significant.

For what it is worth I was advised that Meridian recommend a home run topology for sound quality and I think that the logic is sound. As such I would persevere with trying to get the comms working in a home run topology especially as it seems to work for me. Let me know if I can help in anyway.

Sources: MS600, Fidelity Audio Reference Oppo UHD-203, Roon/QNAP, AppleTV 4K
Processors: Arcam AV40, 271 x2, Lumagen 5348 with Keces P8
Speakers: DSP7200SE FL/FR, DSP5200SE VC, DSP3200 x11, DSP320.2 VOG, DSW x4
Display: JVC DLA-N7 with PK-EM2, Panamorph Phoenix Pro, 128" 2.37 Curved Silver Ticket AT Screen