we dont really know what the other group wants, it might just be as simple to gather all power users with useful powers at one spot and of course make others stop using them, so that those superpowers dont get to known more to common people. (there I go again with my long ass sentences)
What do they want to do after they gathered them? I dunno, maybe just get revenge on the scientists. As I said, we dont know their goal, so we can only speculate.