What's up, RMers?

[BeJeremiah]

Begin by editing Add actor under Game_Party

Code:

def add_actor(actor_id)
    # Get actor
    actor = $game_actors[actor_id]
    # If the party has less than 4 members and this actor is not in the party
    if @actors.size < 4 and not @actors.include?(actor)
      # Add actor
      @actors.push(actor)
      # Refresh player
      $game_player.refresh
    end
  end

Change the "< 4" to the number you need. After that you have to edit the windows that show you party members.