killing coral (on purpose)

[asylumdown]

the box of Walt Smith live rock that I got to 'seed' my tank after my marco rock had cycled never spent any time in a store, I literally got the unopened box directly from the airport. As such, a whole lot of stuff survived on that rock that I've never seen on live rock in the LFS. Namely, there's one species of what I'm positive is montipora that I initially started out thinking 'OH SWEET!' about, but now...

This stuff is both encrusting, and produces branch-like nodules. However, it also grows really fast. At this point, it's now covering a solid 1/3 of the usable surface of some of my best pieces of rock. I'm about 99% certain that this is the same species of coral that actually built the rocks that are now in my tank. It's a tan/pink/light brown colour, so while it's not ugly, it's not something that I probably ever would have purchased on purpose in a store. I have WAY nicer corals that I would rather be occupying the rock space this stuff is taking up. Unfortunately, I can't break it off the rock, because, well, it is the rock. I don't want to get rid of it completely, but I need a way to kill it back a bit. Will a close-up shot of hydrogen peroxide do it? Does anyone have any other methods for selectively killing an encrusting coral?