We have winter tri in Germany, but it's usually a pool swim, then a gap after to allow for drying off and changing. The bike and run are then both XC - bike starts using the "chasing start" method - fastest swimmer goes first, others follow with the same time gap as they were behind in the swim. Then you know if you overtake someone you've moved up a place. Down in Bavaria they have yet another variation using XC skiing instead of the swim.