How to select a paragraph box that is combined with a rectangle using a VBA macro

This seems like a simple thing but the answer is eluding me. I'm writing a macro that identifies a textbox within a group and places text in it. Here's the scenario:

The user selects a group of objects (grouped objects).
The macro loops through the various shape objects within the group until it finds the paragraph frame and changes the story (text) in the box.
The paragraph frame in all cases is a child (combined) object inside of a rectangle.
When the rectangle with text frame are part of a larger group, my code has no trouble looping through and finding the text frame.
But when the selection is only the rectangle with its child text frame, I can't figure out how make this determination and identify the text frame.
If I group the rectangle/text frame combination, my code works just fine. But this is not always going to be the case.

So how can I make my macro find the text frame that is combined with a rectangle?