I'm not sure how many of you actually know how an STS works so I'll try to explain. The air comes from the pump into the first chamber and then the second chamber. The trigger is part of the first chamber. When the gun is fully pumped, both chambers are at a high pressure. When you press the trigger, the pressure in the first chamber decreases because air goes out the trigger hole. The pressure from the second chamber wants to go to the first. So while the air is going from the second to the first, the cap is forced closed and air is released from the second chamber out to the barrel.
(I drew this in paint like 2-3 years ago )
http://i4.photobucke...C/SSPBValve.bmp
(Image wouldn't display here so I posted a url)
So when you connect all the STS's together by the first chamber, Pressing one trigger fires all 4.

I might try putting something like this on the front of a XXL Missile.