I was looking around at materials about psionics in 3rd edition, and came across material talking about "power chains". Supposedly, this was introduced in one of the Dragon Magazines, but I have no real idea what it talked about. I am assuming from what I did find is that it is a grouping of related powers, but I have no idea what sort of benefit the psionicist would get for taking powers within the chain. The reason I am asking is not because I am implementing psionics in my campaign, but I am instead thinking of doing something similar with magic in my campaign I am designing (i.e. where the wizard or sorcerer would get some benefits for taking related spells in a predefined "chain"). I could whip something up on my own, but I just wanted to see what they had (it's always hard to balance things playwise, and always helps to see other materials on a subject, if possible).

Any info on the subject would be appreciated.