Complex sentence: The categories should be merged with their competitor parents (e.g.) and are catered for in the by year structure of the tree at which groups a more manageable and well-connected group of athletes, as compared to a country-based one.
Split into simpler sentences: The categories should be merged with their competitor parents (e.g.). The by sport idea is better catered for through the "by year" structure of the tree at, which groups a more manageable and well-connected group of athletes, as compared to a country-based one.