How do I add commas between the letters of the hostname variable

I'm wondering how I add commas between each letter of hostname variable.  My current script it below.  I need to add commas to slow down the spelling of the hostname when xMatters spells the hostname to a user via a phone call. 

Current example of $event.hostname = Server1

Desired output of $event.hostname = S, e, r, v, e, r, 1

WHILE ($repeat)

  $repeat = false

  @phone::clearDtmf()

   @script::log($event.hostname)

   @phone::play("phrase", "EVENT OCCURRED WITH SEVERITY")

   @phone::play("phrase", $event.severity)

   @phone::play("phrase", "situation")

   @phone::play("phrase", $script.phonesummary)

   @phone::play("phrase", "device")

   @phone::play("spell", $event.hostname)

   $outageTime = $event.creationTime

   @phone::play("date", $outageTime, "ddd m d")

   @phone::play("phrase", "at")

   @phone::play("date", $outageTime, "hh nn")

Thanks for the help.