Can a single universe be controlled by two consoles using the merger function on EN-12 or EN-4?

I’m new to this whole sACN and merging business, so bare with me. I am trying to control dimmers & relays that are on the same universe from two separate consoles and I’m having no luck. My power relays and lighting dimmers are in ETC dimmer racks which are all on universe 1. The relays are used to power up my moving lights while the dimmers are obviously for my conventional fixtures. I have an ETC GIO (sACN priority 101) that I want to use to park all of the relay power on with, while still being able to control my blinders and specials–which are on dimmers–from my MA2 (sACN Priority 100) or any touring consoles that are visiting. Is this possible? And if so, how do I set this up? I’ve tried pretty much every setting on the merger (HTP, LTP, Toggle, Backup) and nothing seems to work. I also made sure that none of the addresses on the GIO are patched on the MA and vice versa. If I set the MA to priority 101 to match the GIO, it kicks the GIO off of Univ. 1 and shuts down all the relays. What am I missing? Is what I’m asking even possible?