This question already has an answer here:
Some time ago I created these two questions: "How to build nested responses in an Apigility driven application with a ZfcBase-DbMapper based model?" and "How to access and manipulate data in Apigility before it is sent to the client?". The first one is mor general, the second one refers to a concrete way of the solution. Anyway, the questions don't duplicate each other.
Now I've finally found a solution for the second question and it's also a possible solution for the first one. I want to post it as answer. Is it allowed to post the same solution for diferent questions? If not -- why?