How can I get my form processing step to work with mulitple picklist if multiple answers are chosen?

I want to include a multiple picklist in my form asking what people are interested in and if they select more than one I want them to get added to one shared list for one selection and another shared list for another selection. For example, if I have a list of items like apple, orange, banana. If they select apple I want them to get added to a shared list for apples and If they select Orange, I want them to get added to a shared list about oranges. If they select both apple and oranges