I agree, I had the same thought about teaming and setting beam weapons so all members could assist on the same enemy. This should be feature that you could change easily at a starbase or something. For all the purist out there, I should think it would be possible in the 25th century to change the color of beams rather easily.
could also add a roleplaying element, for those so inclined.
My engineer was able to create a tighter focus on our phaser array by running it through a modified lens. An interesting side effect, there is a noteable hue change to the beam.