@be_adamant the underlying driver does not support multiple devices. It is hardcoded to pick the first device only. Which one that is you would need to figure out experimentally!
Please file an issue against: https://github.com/nicholasrobinson/homebridge-smartcielo or https://github.com/nicholasrobinson/node-smartcielo
to start a conversation about adding multi device support.
It is interesting that you aren’t seeing any responses on your devices. It is possible that the smartcielo payloads are slightly different to the MRCOOL device. To investigate further you may want to run homebridge in debug mode or file an issue on my github.