Only fights I did with trolls since they implemented 2.0 were those when even was up. Otherwise all my battle energy was used on PvP. So 10 days of farming trolls and getting the event girls dropped is enough to trigger this system to get all 3 new world girls in a row, or they count days even if you don't battle trolls, or they count used energy or actual fights but count PvP in.
As a side note: I to got all 3 girls in a row when I hit new world (12h ago). At least I can continue doing PvP and see how generous are the affection drops in it ;].