Is there a way (in vba) to add nodes to a shape after it's created? Or do I have to add them in sequence as I'm creating the shape?

My situation:
I want to add 3 nodes to a simple rectangle to allow for multiple connector lines to snap to the shape. PowerPoint won't let me edit points on a rectangle, so what I did was convert it to a freeform poly in the same size so I could add nodes to it.

But then I ran into this problem. How do I add nodes after-the-fact?