Stereo Setup without a Network?

[choppedsui]

Hi, I have purchased two reactors for my Shaman to use during ayahuasca ceremonies.  We have the speakers stereo paired, and we are having issues with the music dropping/glitching out over wifi.  This is a problem as he can't be troubleshooting the issue in the middle of the ceremony. It's really frustrating for the attendees when the music glitches in the middle of the ceremony.  He's not tech-savvy, so I need to find a super stable, easy to set up/takedown solution for him.  We have confirmed we are running the latest firmware, and Devialet support has been no help.  Ideally, we would like to find a wired solution to stop the dropping/glitching.  The audio source is an iPhone.  What would be the best way to have cables for connectivity rather than wireless?  We have a lightning to 3.5mm adapter and a 3.5mm to 3.5mm cable, but not sure what's best for connecting the two reactors together.  Would an ethernet cable suffice?  

Goals:
- Stereo sound without a network
- No dropping/glitching of music
- A solution that is easy to take down/setup 
- A solution that's wire-based, not network/wifi based
- iPhone source

Sorry if this has been answered before; I tried searching but didn't have any luck.   

Thanks in advance!