You can do something like instance('RSS')/root/item[name=${selected_town}]/Next_Question in a calculate row. Then you can set the relevance of your question based on that calculation. If your calculate is called next_question, in the relevant column for question se, you'd have ${next_question}='SE'.
See an example of this kind of lookup at https://docs.google.com/spreadsheets/d/1mQGVWaJA4QQp3jtddMdcRSDjc1O-j_bB79GUnlj5k10/edit#gid=0
More generally, you can use any XPath expression to access values in your choice lists.