Changing the 'Roulette' Lore

Is it possible to alter the animation of this spell and change what it does? I've set it up in FF3usME to use the Grav Bomb's animation, and changed all of the targetting and the such so that it is a single target spell selectable by the player, but when cast, it still just shows the pointer that randomly selects a targettable object during battle.

Basically, what I'm trying to do is this: Get rid of Roulette (it's garbage) and change it to a spell that takes on the same functionality as Cyan's Empowerer. It's basically a spell that combines Drain and Osmose together, but I can't seem to get it to work properly. I need to know if I'm doing something wrong, or Roulette is one of those special spells that has all of its functions hardcoded due to its nature.