Found from Devialet's web page...
"Each Devialet in a multi-unit set up must have a dedicated configuration, specifying its role and expected behavior in the chain. The online configuration-tool currently allows you to prepare or edit the necessary configuration files for a two Devialet set-up. Note that each time you modify the master configuration, you must update the slave configuration as well. For set-ups involving more than two Devialet, please submit a new request to our customer care team, we will provide you with the custom configuration files."
So need to contact Devialet.
"Each Devialet in a multi-unit set up must have a dedicated configuration, specifying its role and expected behavior in the chain. The online configuration-tool currently allows you to prepare or edit the necessary configuration files for a two Devialet set-up. Note that each time you modify the master configuration, you must update the slave configuration as well. For set-ups involving more than two Devialet, please submit a new request to our customer care team, we will provide you with the custom configuration files."
So need to contact Devialet.