Is it the Heirs Who Swear Their Oaths of Al-Qasamah

All praise and thanks be to Allah, Alone and may peace and blessings be upon him after whom there is no Prophet, Muhammad, and upon his family and Companions.
As for what follows:

In the eighth session of the Council of the Senior Scholars, which met in the city of Riyadh in the first half of the month of Rabi Al-Akhar in the year 1396 A. H., the Council studied the research into Al-Qasamah, which had been deferred from the seventh session until the eighth session: Is it the heirs who swear their oaths of Al-Qasamah, or is it the paternal relations themselves who swear, even if they are not heirs, if they are adult, rational males?

After the Council had listened to what has been prepared in this. matter of the sayings of the scholars, their evidences, their discussions, and exchanges of ideas, the Council decided by a majority that those of the heirs who swear are the adult, rational males even one, whether they are from the paternal relatives (Al-'Asabah) or not, based upon what has been confirmed in the Two Sahihs in the Hadith of Sahl bin Abi Hathmah. That is the story when 'Abdullah bin Sahl was killed by some Jews. It was narrated that the Messenger said to Huwayyisah, Muhayyisah and 'Abdur-Rahman bin Sahl:
"Will you swear an oath and take the right to the blood money of your companion?

They said: "No." And in another version:
"Let fifty men from among you take oaths.

And, because it is an oath to a claim of rights, it is not lawful regarding the right of other than the claimants, like all oaths. And Allah is the Granter of success. And may peace and blessings be upon Muhammad and upon his family and Companions.

Source:
The Council of Senior Scholars
Fatawa Islamiyah, Vol. 6 Pages 188-189