No, Section III is on Belonging and is a single question that can be answered with reference to any of the prescribed AOS texts. Module B, Paper 2 is either Close or Critical Study which necessitates individualised questions which address specific elements of each prescribed text.
That said...
How are you structuring your essay? With the 2 prescribed texts and 1 related Im guessing you were doing:
Intro
Para 1 prescribed or related? (word count?)
Para 2 prescribed or related? (word count?)
etc
Re: For belonging are we allowed to use a film as a related text if the prescribed tx
You can, but it's not suggested as a wise choice because the concept behind 'related' texts is that they are meant to give you an opportunity to demonstrate BROADER definitions of literacy. I wouldn't...