Possible to cap volume?

I have a tower defense game that I am working on and I’m in the process of adding sounds. Each tower plays its own fire sound when it fires. However When I have 5+ towers of the same type firing at the same time the volume gets louder.

Here is my game as is, the sounds are only in testing stage right now and I am aware that they can get annoying with the current set up.

http://cannedessence.com/icedefense/

Most noticeably are the air towers. if you feel like listening play my game and first place 1 Air (blue) tower on screen. When the first air wave starts (lvl 4) hear the one tower firing alone and then during this stage add a 2nd tower and the volume almost, if not, doubles.

Is there a way to prevent this by limiting the max volume output from flash.