I have two separate lists of different bounding boxes and I am trying to group them by which they intersect the other list of bounding boxes. I can’t seem to figure it out.
Try this maybe:
http://dictionary.dynamobim.com/#/BuiltIn/Action/GroupByFunction
Did you try to type “intersect” in the Dictionary search field? There are a couple of nodes that are commonly used for the task you describe, such as DoesIntersect for instance. See also here:
Had no luck doing it by grouping or shorter way. Maybe I’ll try again at home, but thanks anyway for the help.

