I really enjoy managing Athletic on FM because of the challenge. It's sort of like managing a national team. Are there other teams with a similar policy in the major Euro leagues? If I'm not mistaken, Guadelejara in Mexico has this.
A quick wiki search and I got this 'Real Sociedad, Real Madrid, FC Barcelona, Real Racing Club, Atlético Madrid, RCD Espanyol and Sporting de Gijón.'
No way do any of those teams have Athletic's policy
I did search and found the wikipedia page for Cantera, but as was mentioned, none of the teams you mentioned have a similar setup.Sociedad do, Real Madrid and Barcelona RESERVES do but obviously not the main team, however I agree I'm not sure the other 4 mentioned clubs do
edit: apparently Socieded scrapped their policy in 1989