I have to believe the Rosatos were eliminated (from the earth, not just as a threat). Michael took no prisoners back then. There's no way he lets them off the hook, even if they are "on the run," as Tom put it.
All joking aside, I agree and think that if one had to fill in the gaps between GFII and GFIII they would learn that a young up and coming named Joe Zsa Zsa probably carried out the order, through buffers of course
to take out the Rosato brothers.
The Zsa Zsa character, in my opinion, was loosely based on Joe Columbo.
