I am trying to build a nested macro that contains an iterative macro inside another iterative macro inside a standard macro. I have created the 2nd iterative macro (the one that will be nested within the higher-level iterative macro) without any trouble. In building the higher-level iterative macro, however, Designer keeps changing the macro format to Batch every time I insert the nested iterative macro onto the canvas (specifically when I attach the Control Parameter).
Here is a screenshot pre-Control Parameter:

And here is how it looks as soon as I add the Control Parameter:

Is it not possible to nest an iterative macro inside another iterative macro?