Configuring multiple DataNodes

I have a datadomain with two datamaps, and two datasource each talking to a
different database.

Right now, I have had the datasource configured in the config file, but I
need to remove that and set it programmatically, from an environment
variable.  Simple enough to do with a defauldata source, unclear how to do
when you have multiple data sources and data nodes.

After browsing through the code and the app as it's running, it's unclear
to me how to do this.

Does anyone know the secret sauce?



Tony