I have a list of people and place-names and relationship-descriptions. I want to generate a few places with other info, but in addition, each place will have a list of people there (I can do that), but I also want each place to list relationships for the people there to people in other places. And, I need those other places to refer back through the relationships.

So, as far as I can figure out, I need to generate all that info ahead of time, before beginning to output the places with their people, descriptions, ... But I can't figure out how to make and store that info.