Tell me if this sounds stupid, but you could have amateur circuits that allow a manager to train new fighters as amateurs, and as many as they want (within reason), but then only allow them to take the fighter to the pro level if they have a lack of fighters on the pro circuit. And obviously any manager could put any one of the amateurs on a pro circuit, but if they haven`t worked that amateur to a reasonable level, the new pro will do poorly and that would effect the managers stats, their fault. I mean there doesn`t have to be any money involved, because it is amateur. And if a fighter reached a certain level of competence, then they are either forced to move to pro, be let go, or just not fight until a position opened up. and there could be an inactivity clause on your own amateur fighters, if they don`t see action they just dissapear off your roster.