test.sh

#!/bin/bash

function run_in_background() {
    # The first argument is the name of the PID variable
    # We execute everything passed in argument
    # And save the running pid in the variable name
    local pid_variable=$1
    shift; 
    "$@" & eval "$pid_variable+=\" $!\""
}

function wait_background() {
return_code=0
# We extract the PIDS from the variable name
for pid in ${!1}; do
    if ! wait $pid; then
        return_code=1
    fi
done
eval "$1=''"
return $return_code
}


pids1=""
run_in_background pids1 bash -c 'sleep 5; exit 0'
run_in_background pids1 bash -c 'sleep 1; exit 1'
wait_background pids1