Kotlin filter nested lists I want to filter a list that has episodes of series. The list looks a bit like this: [ { "media": { "episode_number": "7" }, "collection": { "collection_id": "26464" } }, { "media": { "episode_number": "6" }, "collection": { "collection_id": "26464" } }, { "media": { "episode_number": "9" }, "collection": { "collection_id": "123456" } } ] I only want the highest episode number of each collection...