Can you please provide a detailed example including the utterance you used to request the command, the voice response you got back and what was your expectation?
If you intended of having your group item gBedroomRail discovered, you cannot have a group endpoint composed of group endpoints. If you want to have such group available in Alexa, you will need to define its group type and model that item based on the type you specified. The other options would just be to create a group on the Alexa side for your single rail devices. If going with the latter, don’t forget to remove the Alexa metadata configuration on that group item.