Just a note on my setup issues with two Xenon (X1 and X2 we will call them) and a single Argon (A1). I started with just a single Argon and a Xenon in a connected network to the particle cloud, no problem.
The second Xenon(X2) was added to the network after those were running for a couple days but not without some issues. The Mesh network would not allow the newest Xenon(X2) to connect to the cloud by only placing the first Xenon(X1) into pairing mode.
The trick I needed was to place the Argon(A1) and Xenon(X1) into pairing mode and once the Xenon(X2) was looking for the cloud take the Argon(A1) out of pairing mode.