(1)An agreement among part-owners of a business which says that, under stated conditions, i.e., disability or death, the person withdrawing from the business, or his heirs, are legally obligated to sell their interest to the remaining part-owners, and the remaining part-owners are legally obligated to buy at a price fixed in the agreement; (2) a similar agreement between an owner or part-owner of a business and a non-owner, such as a key employee.