what are the listed join years for this league?
1954, 1960, 1950, 1950, 1960, 1977, 1950, 1950, 1964, 1940, 1950, 1950, 1976, 1950, 1976, 1956 2nd: 1964, 1974, 1950, 1960
which of those entries has more than one year?
1956 2nd: 1964
to what high school do those join years belong?
lakeville