I've heard of something like that, but I don't know how it goes... I just play 9-ball. If you want to work on safeties, play safe more! The opportunaties are always there.
Speed control, tangent lines, and kicking systems come into play for safeties; if you are having trouble with safeties in general (or would just like to improve your safe-game) I would suggest isolating your practice to one of these three seperately. The sum of the three result in excellent safety-play.
Not to sound condisending, but here are a few safeties to look for:
1. When there is another ball very close to the object ball, get shape for the safety and play a stop-shot to "knock the object ball out of there."
2. With ball-in-hand, you can almost always follow up to another ball...it's easy to get, but speed control is how you really hook someone.
3. When there is a ball (or multiple) on the long-rail near the corner from 1 diamond to 2 diamonds out, line up your tangent and slow roll up in that mess.
4. When the object ball is on the rail and another ball is about a diamond out from hit, softly bank out the object ball and follow up behind the other ball.
5. When two balls are straddling the corner pocket, you can use the 2-rail kicking system (parallel to the midpoint through the pocket) and use the tangent right down that path to hook someone behind the other ball.
Take note of #5 here, it combines all of the three. Kicking systems can help you find a line to hook somebody, like a roadmap; then all you have to do is match your tangent line to it, and watch your speed.