Your description is not exhaustive (e.g., what if persons 1 and 2 are both selected? Is it even possible, or is there a constraint preventing it in the first question?), but based on what you tell us, I would sum up the behaviour that you want as follows:
- If person 1 is selected in the first question, location B does not appear in the second question.
- If person 2 is selected in the first question, location A does not appear in the second question.
Is that correct? If yes, I found a way to do that by looking at this thread, which made me realise that the name column of the choices sheet can actually be used as a variable in a choice filter (I had never thought of that).
What makes your case different from the usual examples given for cascade selects is that your first question is a select_multiple instead of a select_one. But using the name values for locations A and B, we can achieve the two above bullet points with the two following filters, respectively:
not(selected(${person},'pers1') and name='locB')not(selected(${person},'pers2') and name='locA')
So your complete choice filter would be combining those two as:
not(selected(${person},'pers1') and name='locB') and not(selected(${person},'pers2') and name='locA')
Here is example form where this is applied: Filtering_out_from_multiselect_value.xlsx (8.7 KB)
There might be a simpler or more elegant way to do it, but I don't know how.