Hi,
You can create a new pipeline with your requirement and define the same in filebeat.yml file with pipeline tag as below.
# The Ingest Node pipeline ID associated with this prospector. If this is set, it
# overwrites the pipeline option from the Elasticsearch output.
pipeline:
Please check below link for more understanding.
https://www.elastic.co/guide/en/beats/filebeat/master/configuring-ingest-node.html
Regards,