Logstash client feeding inputs to another Logstash

I have an ELK stack setup working well. Next, I have installed only Logstash clients on specific systems from where I am expecting logs to be generated for ELK processing.
How can I configure/write an input plugin for Logstash in ELK stack to accept input logs from another logstash client running on some other system.
As per the documentation, logs can be inputted from any source, but is this story really possible or am I going in wrong direction?
Thanks in advance for help.

You can e.g. use a lumberjack input/output pair to have a Logstash instance pass logs to another one.