I am just guessing that after all games in a "cohort group" are played, the next (different) "cohort group" (with 4 teams that did not play yet against each other) will be formed and then those teams will play against each other and so on until all games are played in Cohort Cup division (changed now from Covid Cup to Cohort Cup as per VMSL web page).
This is just a guess.
As I understand it there will be a Europa league type setup. So probably the top 2 from each group in one Knockout style tournament, and the bottom two from each group in another Knockout tournament.