A service unit must define only one JBI component dependency as component on which it must be run.
But we can need to define other JBI component dependencies to extract service provider contracts or resources. These components will not be used to run the service unit.
So, please add a check on phase 'validate' of project Maven lifecycle to check:
	- for a service unit: only one JBI component dependency is defined to run the service unit,
- for a service assembly: its service unit dependencies must define only one JBI component to run the service unit.
And if more than one JBI component dependencies are defined, we must define the JBI component used to run the service unit at Maven Petals plugin, through the parameter '
jbiComponentUsed'. The JBI component required to run the service unit will be added as extension in the service unit JBI descriptor, so it is required to have the parameter '
updateJBIXml' set to 
true. This extension will be used when packaging a service assembly.