Few people would ever allow someone else to choose their business partners if they were founding a company, but this indirectly happens quite frequently in family enterprise. Thoughtful and forward planning parents pass on the assets they worked so hard to build or steward to thier children, who then become business partners in addition to being siblings (or cousins).
While being partners in a family enterprise is deeply rewarding for many, each generation must reaffirm the partnership and work towards alignment in family and shareholder goals for the business and family relationships to function. Sadly, many family business members experience and focus on the stresses or conflicts in working together without every trluly exploring why they want to be partners in the first place, regardless of how they came into the partnership. Focusing on the latter is far more likely to produce the secure bonds that will allow both family and business partnerships to flourish.