Soul that splits in seven parts

I clearly remember reading somewhere about (some branch of) Buddhism believing that there *is* a soul and that it splits in seven parts when dying. The article mentioned that four of these parts are believed to return when reborn, the other three will merge with Nirvana. My recent reading has taught me that the individual soul/ātman does not exist *per se*, it is a false assumption and what one might perceive as "I" is just a piece of the a bigger consciousness (God, if you like). Can anyone shed any light on the splitting? And is my current understanding correct, incorrect or oversimplified?