Does Raúl Alcalá have a grandson? If so, some of the younger participants at the Gran Premio New York City last year could eventually race against said grandson, making it the first case of racing against both grandfather and grandson.
Not sure if it was mentioned earlier, but I have a feeling there are quite a few people who've raced CX against both Sven and Thibau Nys.
I was unable to find any races where Sergey Sukhoruchenkov and Raúl Alcalá both started unfortunately - I thought it could be possible Alcalá would face both Sergey and Bogdan Zabelinskiy, his grandson via his daughter Olga Zabelinskaya, but it seems politics prevented it; Alcalá tended to run a North American and Tour de France-based program, while the Soviet teams tended to do Open races and the Vuelta. Sergey did the Vuelta twice and the Giro once before the fall of the USSR, while Alcalá only did the Giro once during Soukho's active career and didn't enter the Vuelta until after his retirement - sadly Raúl did 1988 and Sergey 1989.
Obviously it would be extremely difficult to pull off such a feat because you'd need multiple father-son combinations within relatively short periods of time to be able to pull it off - for example here, Sergey's final year of competition was 1990, while Bogdan's first recorded results on a notable enough scale as a junior come in 2023, meaning you would need a 33-year spread of results to race against both. For context, the only rider I can find other than Alcalá who could even theoretically reach that spread was Davide Rebellin, with 34 years from first to last results (1988 as a junior through to 2022 when he finally stopped racing and sadly passed away). The longest-running active pro is Óscar Sevilla, who has a 27-year spread from 1998 to 2025 - but would have been racing as a junior and espoir before that, it's just that he didn't compete in junior championships or anything like Rebellin did to appear before his Kelme years. Muradjan Khalmuratov is only one year behind him, though - he debuted in the Junior Worlds in 1999 and is still active today.
Likewise I looked at the Amplers, as Klaus' son Uwe's son Rick went on to have a minor career in the sport as well; Klaus' final year of competition was 1970, and Rick's first was 2006, giving a 36-year gap. This is harmed by the tendency of the amateur riders to quit at a younger age back in the Ostbloc days, Klaus retiring at the age of just 29. Soukho raced on until he was 34 with the chances to race with Alfa Lum at the end of the 80s, which gives a bit more of a chance.
For this reason I would think that a family like the Rujanos are your best bet for a possibility for this, as Jeison is only 19 years younger than José, but José is also continuing to enter races now well into his 40s , meaning if Jeison has a son himself relatively soon, it's possible that somebody relatively young racing now - especially in the insular Venezuelan scene where they could continue to race the domestic races for years to come, especially if they're local
Tachirense talents - could still be racing at least part-time when said son starts to compete. Take somebody like Arlex José Méndez, who won a stage of this year's Vuelta al Táchira racing against both José and Jeison, and is still a teenager. He could feasibly still be racing when somebody born today is entering the race themselves.