Conditional lookup field


I don’t know how to do this. To simplify, let’s say I have 2 tables, one called topics with a list of article topics, and one called content with a list of articles, with a single select field categorizing the articles by country. In the topics table, I need a look up field of the articles per country - for now I just have one lookup field that shows all the articles, in all countries. So I need some sort of formula that would say “only show me the articles from the articles table which have the single select field of [country]=Belgium”
Hope this makes sense - and hope it’s possible!

Thank you :slight_smile: