I've not had pairs or groups of WW's but i'm sure they are like other dwarves and if so, they will have little squabbles.
You will probably find one is more dominant than the other, this will cause little arguments between them. Just make sure that the less dominant is getting food and water and keep an eye on them every day to check they haven't been having any major fallouts/fights.
Have you got two of everything like, 2 wheels, 2 houses/beds etc? Also, when you have them out, try to make sure you handle them both and possibly rub your hands in their bedding to get their scent on you.
Hope this helps a bit, i'm sure amore experienced dwarf owner will come on soon though and add to what i've said