I have 2 Inovelli Red Series dimmers, V2 (LZW31-SN) that control my kitchen and dinning room lights. I went into Rule Machine and was able to set them both up that double tapping either one up turns them both on to 100% while double tapping either one down turns them both off.
Alexa will dim/brighten either one. (e.g. Alexa: Set [Kitchen/Dinning Room] lights to X%). However, I want to have Alexa dim/brighten them both at once. I created a Group in HE (cleverly called "K D Lights") and Alexa turned them both on/off when I told her to turn the K D Lights on/off. However, if I say: Alexa, turn the K D Lights to 50% nothing happens. (But in the log I see it sent the command).
My son (30-something) told me how to do it. First I removed the HE KD Lights from Alexa and then I removed the the KD Lights group from the Groups and Scenes app. I then created a KD Lights group in Alexa and added the Kitchen and Dinning Room lights to the Alexa K D Lights group. (Under Devices you can create a new group). That did it. So now I can tell Alexa to not only turn the K D Lights group on/of, but I can also say Alexa turn the K D Lights to X%. Yea!