something that tom was sensing after the five families meeting?

during the meeting with the five families and the other dons around the u.s, it was when vito was making his statement to tattaglia about foregoing vengance when tom sensed that something was "missing" from the puzzle. it was as if vito had something else up his sleeve but tom couldn't figure it out what it was and he couldn't bring himself up to ask. this missing piece of the puzzle that tom was sensing, was it vito planning the hit on barzini and tattaglia? or is it something else? (btw, i don't have the novel on me, so i apologise if the question seemed to vague)

The novel provides the missing detail. After the meeting, when the Don back home, meeting with Tom, he (Tom) says that he doesn't believe the Don doesn't want to know how Sonny was set up, or that he has given "your enemies the victory today...you've constructed a magnificent riddle that I can't solve." The novel then says that an "immense look of satisfaction came over the Don's face...well, you know me better than anyone...even though you're not a Sicilian, I made you one. There's an answer and you'll comprehend it..."

thank you turnbull for the info... i'll read the novel more carefully on that part...