Why don't you just make a white "muzzle flash" picture in photoshop with a blue background, then chroma key it until you get a nice feathered effect, and put the opacity right down. Make this 6 frames long, and key frame the opacity and the shape to go up then down as the shot progresses. Then just put that over all the blaster nozzles. You can adjust the opacity depending on your view. also, you might want to make it more yellow.