Although Jacob is certainly aware of the consequences of intra-family jealousy, he seems to encourage it. After he has received a bad report about the brothers from Joseph, Jacob sends him out to see how they're doing and to report back to him.
Knowing what Joseph is thinking and saying, the brothers decide to get rid of him. The first-born, Reuben, and the fourth-born, Judah, step in to stop the murder. Instead, they sell Joseph as a slave to some traveling Ishmaelites (hear the echo of the rivalry between Isaac and Ishmael?).
Spoiler Alert: Coincidentally, or providentially, Joseph's dream will come true. Read Psalm 105:16-22.
When he summoned famine against the land, and broke every staff of bread,he had sent a man ahead of them, Joseph, who was sold as a slave.
His feet were hurt with fetters, his neck was put in a collar of iron;
until what he had said came to pass, the word of the Lord kept testing him.
The king sent and released him; the ruler of the peoples set him free.
He made him lord of his house, and ruler of all his possessions,
to instruct his officials at his pleasure, and to teach his elders wisdom.