Ralphrennick makes a good point, and one that I often marveled at.
But it does happen. In orthopedics, two of the biggest names in knee biomechanics (Maquet and Pauwels) happen to have come from nearby towns in Belgium and lived around the same time. And yet, even so, they didn't live in the exact same town and meet when they were teenagers!
With the Beatles, you also have to add Harrison and Starr. Neither is/has been a genius, but as often noted on this Forum, they fit in perfectly!
In music, you'd have to go with Mozart and Bach and a couple of ...