(range 1200-1299, 243 players, 9 players per group, advance per group: 3 players, concurrent games per opponent: 1, 3 days per move,  no vacations).

Normally:
A`Round: 243 players (=27 groups X 9 players)---[advance per group:3 players]=>
B`Round:   81 players (= 9 groups  X 9 players)---[advance per group:3 players]=>
C`Round:   27 players (= 3 group   X 9 players)---[advance per group:3 players]=>
D`Round:    9 players (= 1 group   X 9 players).
but, if more than 3 players per group advance to the next round, due to the same score and tie breaks, then it will be different.