Complex sentence: There are hundreds of professional and amateur football teams in Poland; which are organized into the national 1st league and 2nd league, 4 regional 3rd leagues, 18 regional 4th leagues, 49 regional 5th leagues and a variety of other lower level leagues.
Split into simpler sentences: There are hundreds of professional and amateur football teams in Poland. The football teams are organized into the national 1st league and 2nd league, 4 regional 3rd leagues, 18 regional 4th leagues, 49 regional 5th leagues and many more lower level leagues.