Personally, I feel like the complexity of splitting them up argues against doing it! If I was going to nominate Kassandra/Layla Hassan, for example - two characters who physically meet in-game - it'd be a crossover between Odyssey and Modern Day with your example.

I also feel like people will just generally offer/request the characters they're familiar with, so - to me, at least - it isn't worth the split. Just my two cents, anyway!