I know this is older but I ran across this post when testing this scenario. The _TCP_ROUTING method in "Route inputs to specific indexers based on the data input" in the docs worked as advertised with the stream input for me.
... View more
Just as an update to this post as it may be out of date. I was able to successfully test _TCP_ROUTING for stream. The documentation at https://docs.splunk.com/Documentation/Splunk/latest/Forwarding/Routeandfilterdatad under the heading "Route inputs to specific indexers based on the data input" does work for the stream input.
... View more