Does the obscurity of a narrator’s identity disappear if two narrators report from him, while the chain of transmission to one of them is not established?

The questioner : Shaykh, here, if a narrator has two narrators reporting from him, and the chain of transmission to one of them is not established—meaning, in the chain of transmission to the trustworthy student, this student is weak—does this count with the first one as removing the obscurity of the identity, or is the criterion what is established in the chain of transmission to him from the narration of only one narrator?

The Shaykh : If the chain of transmission is sound.

The questioner : And it remains with the obscurity of the identity.

The Shaykh : Yes, exactly.