Antonio was the underground emperor of all of New York, so when he summoned those gang leaders, every one of them responded eagerly and promptly.

Moreover, Charlie's instructions to Antonio were quite misleading. Antonio acted according to Charlie's instructions and told the gang leaders that he had a very important business deal to discuss with them in person. He also instructed them to bring their most trusted confidant to the roast goose shop in Oskiatown for a confidential meeting.

Further