Is there a way to specify a custom Python transformation stage on the way from Source to Destination?

[EgorKraevTransferwise]

Airbyte looks like an awesome tool; however one thing I couldn't find is a way to specify a custom transform while loading data. For example, I would want to apply a custom chunking algorithm to incoming Confluence pages, eg calling LLMs to do it, whatever, and then load the resulting chunks rather than the raw pages (so one-to-many transform).
Is there a graceful way to do this right now? Seems this would multiply the power of Airbyte by a lot.