It doesn't appear to have a name, actually! I did do research on that line, way back when. "Sororicide" would presmably be the killing of one's sister and/or a pledge house, but aunts? Nothin'. You'd really think we'd have something by now!
Timing and comics being what they are, I made the last few pages over the course of some family celebrations last autumn. How much life influences art I shall not elaborate.