Getting nth data

[Matt2012]

In my use case I want to get all results for a certain nth depth.

 "rest": [
    {
      "mode": "server",
      "resource": [
          "type": "AllergyIntolerance",
      "resource": [
          "type": "MedicationStatement",

So I want to return all resource types:
i.e.
["AllergyIntolerance","MedicationStatement"]

Is that possible?
The nth example does not link anywhere?