Is there's a direct way with schematics to not only define models related to a JSON schema, but also specify how to populate it with data from another JSON schema?

For example, suppose I have a system with an internal schematics model specification, but I need to fetch data from a third-party service (or several) which gives me the data I need, but in a JSON satisfying a JSON schema of different structuring:

• fields might have different names;
• field values might have different formats;
• internal fields might need to be inferred from multiple third-party fields;
• fields, in any level of depth, might be represented in a flattened manner in one side and nested manner on the other;
  Ex: {"weather_temperature": 75, "weather_wind": 100} as opposed to {"weather": {"temperature": 75, "wind": 100}}
• third-party objects might need to be aggregated or disaggregated in order to fit the semantic of the internal schematics.

In the end, what I'm searching for is a simple, preferably declarative way to specify, for each of the fields present in my internal schematics representation, where is the related information present within a different schema, in a way that I'm able to simply feed the third-party JSON to my outer internal model's constructor.