#!/bin/bash

setvar command = ""printf 'a\nb\nc\n'""
mkfifo first
mkfifo rest0
shell {eval $command | tee >(head -1 > first) | tail -n +2 > rest0 &}

cat first

mkfifo rest1
shell {cat rest0 | tee >(head -1 > first) | tail -n +2 > rest1 &}

cat first

mkfifo rest2
shell {cat rest1 | tee >(head -1 > first) | tail -n +2 > rest2 &}

cat first

mkfifo rest3
shell {cat rest2 | tee >(head -1 > first) | tail -n +2 > rest3 &}