The spell familicide

[fictionfan]

In the comic order of the stick page 639 a spell called familicide is cast. A spell which has the effect of killing every living creature that shares the targets bloodline and every living creature that is directly related to any of those creatures is also died and so on and so forth. I can't seem to find a way to state this in D&D, but GURPS is known for being able to do anything so can the spell or power that has the same effect be made?

here is the comic page http://www.giantitp.com/comics/oots0639.html