thanks for the reply. We do split them, and have always done it that way (A on one side, B on the other). I cut a slot in the snow with my chainsaw the day before the race, and run the wire in that. It works fine with no interference. I just wanted to confirm that this is commonly done, but gauging by the lack of replies, maybe it's not!
In any case, they are only homologated for one more year, so I'll have to replace them soon.