What formats can a league run for younger and older players?

Little League divisions: a league may run one competition at each of Little League-Major, LL-Minor Player Pitch, LL-Minor Coach Pitch and/or LL-Minor Machine Pitch. Little League International guidelines say the ratio of Minor to Major teams in a league should be no greater than 2:1.

Teenage divisions: a league runs either (1) separate Intermediate League, Junior League and Senior League competitions, or (2) Senior League only, in which all players of League Age 12 through 16 are eligible. In the Senior League-only format, leagues can run grades called SL90, SL80 and SL70, which use the regular season rules of Senior League, Junior League and Intermediate League respectively.

Source: Baseball Australia, Little League in Australia: Australian Governance (August 2024 edition).