Thanks for your help @erfajo!
I was able to find that node in a BIM4Struc Package. Unfortunately, I found some Python problems after that…
After watching this post very closely, I was able to get my lists sorted correctly for the custom node to rotate multiple assembly origins.
https://forum.dynamobim.com/t/assembly-modify-origin-part-2/18995/12?u=wadenolandba
Onward!