With the way Belichick has staked out a claim it's hard to track them as seperate trees. NFL coaching is a lot like 70s heavy metal, everybody's related to each other at some point.
It's just a case in point that good head coaches will build good staffs and these people will go out and make their mark on the world. Bill Walsh' lineage has been the most impressive. 3 SBs for him, 2 for Sieffert, 2 for Shanahan, 1 for Holmgren