The Sixth family book has several passages and testimony of Salvatore Vitale. It seems to support that ties were severed with the killing of Gerlando Scascia.
I made a small outline of what was said in the book.

-Gerlando Scascia was killed in March 1999.
-Massino tells Vitale that no one is to know who killed Scascia and to keep it a secret.Massino didn't want Montreal to know he ordered the killing
-2001 Massino made one last attempt to bring the "Sixth family" into line. The elimination of Scascia severed New York's direct link to Montreal. Massino had first sent Frank Lino,then secondly Anthony Spero.
- 2001 On the third time he sent Salvatore Vitale & Anthony Urso
Vitale tried to offer Vito Rizzuto the position of captain but Vito evaded the question and changed subjects.
-Vitale heads back to New York to report to Massino. Massino gets upset because the talks did not go well.
- Vitale was caught on conversation complaining that a captain in the Bonanno has fewer than 10 soldiers and some captains have as few as 3 soldiers. "We don't have enough men Vitale" said.
The author goes on saying it was a fool's offer to Vito who commanded twice as many made Bonanno soldiers in Canada and made men in the Sicilian tradition.
-Jun. 2004 Vitale now informant was asked,"does the Bonanno family operate outside of the United States?"
Vitale replied "yes". He said it was Vito Rizzuto, he was later asked what position does he hold and Vitale replies acting captain. Vitale made reference that Vito as being in charge of Montreal but not having accepted the invitation from Massino to officially be named a captain. (This made no sense)

The book went on to say that it was Vito that called the shots in Montreal not Massino.