Ideas for getting GSP off rock??

[incept]

As the title states, I have some beautiful, very bright and healthy GSP. Problem is it is growing to well as normal and starting to crowd and choke other tank inhabitants out. Namely a Chalice which I am quite fond of. There is also another SPS that I am getting worried about if I can't scale it back. I've tried to peel, pick, tear, pull, pry and harass the GSP off however short of pulling the rocks out which have been drilled and pinned in a big formation and taking a blow torch to it I am not sure what else I can do.. Looking for ideas please... Im a pretty new person to the saltwater arena, this tank has been up for just over 2 years now and has finally started to go good. It is on a very coarse rock, Not Fiji, or Tonga or Marco rock. Not really sure what type it is... Anyhow, I am very open to suggestions please and thank you...