I agree with regal. By the theory of organismal antagonism only one organism will occupy a specific niche; however, I must state a caveat: bristle worms, IMHO, serve a great purpose in your clean up crew, but just like humans, some will have a specific taste for a specific food type eg native southerners like myself cannot drive past a Bojangles without grabbing a Cajun fillet biscuit. One worm in your entire population (that has an acquired taste for softies) can do a, well, fecal load of damage. It would surprise you how many bristles you have in your aquarium. If you doubt me, just take out a small rock and dip it in Revive (or FW melafix) and you'll jump at how many worms fall to the bottom within 15 minutes. One easy way to control the population growth is natural mediation by a 6 line wrasse and a coral banded shrimp. The wrasse will eat tons of small worms and the coral banded will eat pretty much everything.
This being said, IMHO, bristle worms serve a great purpose in tank maintenance overall. So, even though you mediate their population with natural predators, you will "see" a difference in population swing of another organism that will utilize the nutrients that the bristle worms were eating. One more caveat: the reason I prefer natural intervention to chemical is that the population size will change more slowly; therefor, the natural cycle of life(population wax and wane) will take place with very little "Spikes" in either algal growth or other organisms.
With products like a Praziquental or other chemical means you will take out an entire niche of your ecosystem and therefor leave all of those nutrients available for simply another organism to utilize, not to mention the excess nutrients released by the rotting carcasses of the target organism. You see the dual negative effect aye?
Once again in closing, let me say that just as in multivariate calculus, there are a multitude of working solutions for any one given problem, and this is simply my preferred solution that has worked best for me; however, you tank is not my tank, and your variables are different than mine so my solution may not be the best for your problem: if I were a betting man, I'd roll with it though