So I have an idea and it may work since there are only 2 factions in the game.
We have 2 Conferences Amongst The Regiments
Union vs Confed
We play a regular season of each Confed regiment vs each Union regiment, the regiments on either side to win the most rounds after all regular season matches will be given the #1 seeds in their conference and receive a bye in the first round of the playoffs.
Regiment leaders must agree on a map during the regular season
If a map is not decided a duel or coin toss by a ref can decide which map is chosen.
Then we could do a system of Confed vs Confed and Union vs Union until the top 2 regiments remain
All playoff losers before the Semi Finals will be moved down into the Silver League, where their own playoffs will continue until a Silver League winner is chosen
Seeding based upon Regular Season Seeding not where you placed in the playoffs.
Or
we could do a system of the top half of Confed vs Confed and top half of Union vs Union until the top 2 regiments remain
(Basically NFL Playoffs)
Or Finally
We could do a Union vs Confed mixed Bracket based on seeding of the round robin
In the playoffs the regiment with the highest seeding will be allowed to choose the map they will play.
(homefield advantage)