So, this is an alternate universe where Tommy and Paulie did the bank heist, they both succeeded, and they both started living their own lives. And Sam misses his friends, so he sends them a postcard.
Three years. It had been three years since Tommy and Polly had ran off. The two had pulled off the biggest heist ever, and they got a pretty big share of the money because they did it. Each of them left and started their own lives, until one day, the two of them get a postcard. The two of them decided to meet up. They wanted to see who the postcard was from, and what they said. So they met up at a nice restaurant.
The postcard was from Sam. At first, they were really mad that he of all of the guys had sent them a card. Until they started to read what it said. Both cards had said the same thing. It talked about how Don Salieri had quit. He was too old, and he was getting tired of doing this, so he passed it on to Sam. And Sam missed his friends. He must how the three of them would always go and do something, and he missed how they were always together. He wanted to contact them and see them, but most importantly... he just wanted his friends back.
As Paulie and Tommy both read the card, The two of them began to think. So they both sent a reply back, hoping that Sam would get it. They both wanted their friend back too.