Lagom - Publishing messages to 3rd party kafka

I have built a lagom service (transaction_service) integrated with an internal kafka cluster that uses Lagom message broker api for intercommunication/event streaming between the services in the system. I need this lagom service also to consume and publish messages from/to another 3rd party kafka cluster (in an external system not built on lagom). The subscriber part is implemented as described here. But, I couldnt find a way to publish to the 3rd party kafka cluster. Is there a way to achieve this in lagom without any other library support?