I have 3 Macs running iTunes: laptop, desktop, and one entertainment center. I also have an Apple TV ver.1 on another TV. I'd like to be able to stream audio from my laptop to the ATV and the entertainment center Mac, preferably using Airtunes. I'm aware of various streaming apps, but none of them have the synced audio of AirTunes, so they wouldn't work at all to "fill my house with music". Is there a way to configure iTunes to act as an Airplay server?