In the fifth season of The Sopranos, New York guy Joey Peeps is killed by Tony Blundetto. Johnny Sack, his mentor, doesn't find that out until later on, but even before he finds out, Tony's crew in Jersey are the ones handling Peep's tombstone.

This doesn't make sense to me. Why would this happen? Do things like this happen in real life where say, if a soldier in the Gambino Family dies, the Genovese family would pay for/arrange the tombstone?

Haha, hilarious scene!

I think they just did it as a nice thing to do for Johnny Sack when he was going through a sad time to curry favour with him.

I'm sure Tony and crew paid for it because they had or knew of a business that did tombstones. I'd imagine even though different families or crews they give each other business or help out where they can. It still is a Fraternity criminal or not.