AirPort Utility 6.2 does not provide this type of feature.
If you install AirPort Utility 5.6, you could use that version to set up the AirPorts to flash green on activity. AirPort Utility 5.6 was designed to run on the Lion operating system. You will need to use a workaround mentioned in the link below if you want to install AirPort Utility 5.6 on Mountain Lion, since Apple's installler will not allow you to do this.
This is not supported by Apple. It does work for me as well as others, but there is no way to predict whether it might work for you.
http://www.macworld.com/article/1167965/mountain_lion_and_the_ancient_airport_ba se_station.html