Sayyiduna Imran bin Husayn (may Allah be pleased with him) says that a man had six slaves and had no other wealth. He freed them at the time of his death. The matter reached the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) disliked it. Then he (peace and blessings be upon him) divided them into three groups, then drew lots between them, freed two and kept four in slavery.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21394