Everyone here makes good points. I feel like it is never fully explained.

In my opinion, Tony was in his father's crew which is inherited. That is definite.

Jackie would seemingly be a member of his brother's crew as well, most likely inheriting that and in theory maybe starting the trend of the Aprile Crew bosses dying early.

If this were the case that Jackie ran Richie's crew after the 1990 bust that put Richie away, it would explain having Ralph, a notoriously strong earner running point on Florida operations. A Jackie backed Aprile Crew would have the ability to reach out and have a satellite crew in Miami as well.

This would leave to question who was maintaining the Aprile Crew as day to day boss for Jackie both while he was Acting Boss and while he was sick, but in theory with Jackie being made Boss outright, his entire crew may have become made solider's with increased freedom. They were all kicking direct to Jackie as their Capo, now as Acting Boss they would all still be direct with him and kick up as well, but their structure from crew to individuals would likely be increased as Jackie would oversee the family day to day and continue to loanshark heavily, while his former crew were likely left to operate freely as long as they paid tribute on their various respective ventures.

This could likely explain why early on there is no Aprile crew capo involved in the meetings behind Junior's back with (Tony, Larry, Ray, & Jimmy Altieri) yet soon after Tony becomes outright Boss he begins to need to "get the Aprile Crew in line" because nobody knew who was in charge as I believe many of them had been operating more freely over the past years during Jackie's reign and were active in other areas of the state than the Soprano Crew.