What is the title of a movie (mid 80s) about two rich families involved in a feud that has something to do with industrial problems, maybe factories, and possibly mafia problems. There is another story line about father-daughter relationship. I remember the father had meetings with mafia (?) people at the house on the lake. At the end of the film there’s a shot of a big boat on the lake, and a huge explosion, in which everyone gets killed, and this is the ending (I think the final shot is that big explosion).