The Messenger of Allah ﷺ ruled that the right of preemption applies to property held jointly by partners that has not yet been divided. But once the boundaries have been marked out between them, there is no right of preemption in it.
حدثنا يحيى عن مالك عن ابن شهاب عن سعيد بن المسيب و
أن رسول الله ﷺ قضى بالشفعة فيما لم يقسم بين الشركاء فإذا وقعت الحدود بينهم فلا شفعة فيه