To fully utilize the hierarchial configuration strcuture, I often define an 'abstract' top level configuration in which the build steps are defined in a 'virtual' manner, for example I can serial composition of steps: checkout, build & deploy.
However, child configurations might override one or more of these steps. It is sometimes usefull to have a dummy step on the top level, similar to abstract method in a Java superclass, in which you can override it in the child configurations. My current workaround to this is to a step that will never run.