I'd not be inclined to do it now......January is just not the most ideal time for this type of activity nor is it best suited to the plant. Ideally, midsummer to early fall is the recommended time for this process, as bearded iris enter a period of semi-dormancy about 6-8 week after blooming that allows division and transplanting with minimal stress or transplant shock. You can also do this in early spring, but will most likely be sacrificing most, if not all, of this season's blooms.

I'd be concerned that doing it now would subject the rhizomes to rotting in the cold wet soil. Summer is best, fall is ok, but January is probably not a good idea.