Complex sentence: Hartford became the home of the WHA's New England Whalers in 1975 after the club moved from Boston, one of four WHA teams that joined the NHL in 1979.
Split into simpler sentences: Hartford became the home of the WHA's New England Whalers in 1975 after the club moved from Boston. The Whalers would be one of four teams from the WHA that joined the NHL in 1979.