Organized output of numbers from multiple goroutines

The program runs three goroutines, each printing numbers from its own array. It is required to modify the code so that the numbers are output in strict order, while the call to fmt.Println() must remain inside the loop of each goroutine.

package main

import (
        "fmt"
        "sync"
        )

func main() {
    var waitGroup sync.WaitGroup
    waitGroup.Add(3)

    go func() {
        for _, v := range []int{1, 4, 7} {
            fmt.Println(v)
        }
        waitGroup.Done()
    }()

    go func() {
        for _, v := range []int{2, 5, 8} {
            fmt.Println(v)
        }
        waitGroup.Done()
    }()

    go func() {
        for _, v := range []int{3, 6, 9} {
            fmt.Println(v)
        }
        waitGroup.Done()
    }()

    waitGroup.Wait()
}