Al-Kāfi - Volume 5 > Separation of Slaves from their Relatives (Is Not Permissible)
Hadith #2

2- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ سَمَاعَةَ قَالَ سَأَلْتُهُ عَنْ أَخَوَيْنِ مَمْلُوكَيْنِ هَلْ يُفَرَّقُ بَيْنَهُمَا وَعَنِ الْمَرْأَةِ وَوَلَدِهَا قَالَ لا هُوَ حَرَامٌ إِلا أَنْ يُرِيدُوا ذَلِكَ.

2. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ‘Uthman ibn ‘Isa from Sama‘ah who has said the following: “I once asked him (the Imam), ‘Alayhi al-Salam, about the case of two slaves who are brothers; if they can be separated from each other or a woman slave, if she can be separated from her children. He (the Imam) said, ‘No, it is not lawful unless they want it.’”