code: protected Collection<BioPAXElement> generate(Interaction inter, Set<Entity> taboo)
  	{
  		Set<BioPAXElement> simples = new HashSet<BioPAXElement>();
  
  		for (Entity part : inter.getParticipant())
  		{
  			if (part instanceof PhysicalEntity && !taboo.contains(part))
  			{
  				simples.addAll(linker.getLinkedElements((PhysicalEntity) part));
  			}
  		}
  
  		return pe2ER.getValueFromBeans(simples);
  	}
docs: Gets the related entity references of the given interaction.
  @param inter interaction
  @param taboo entities to ignore/skip
  @return entity references