What's the easiest way to achieve this?
EDIT1: I have figured out a way to do this. I don't know if there is a better way, but it can be achieved reliably by giving your second set of jump through platforms a unique qualifier and having an event as follows:
+ Test for obstacle overlap
+ Player box is overlap group.whatever
+ Object is falling
+ Y ("Player box") = Y ("group.whatever")
-> Selected object overlaps an obstacle
This allows you to stack 2 "jump through" platforms on top of one another.