My first guess is name resolution. Try a static mapping within the HOSTS or LMHOSTS file that refers to the various domain controllers. (You didn't specify whether the domain in question was Win2k or NT4. The former uses DNS for name resolution, the latter uses WINS.) Or, if you don't mind solving a problem by throwing money at it, there's a useful little utility called Multi Network Manager from Globesoft. It not only allows you to set up different IP addresses (and the associated gateway and subnet mask information), it also allows you to specify different domains, network shares, printers, etc. I find it quite useful and easy for the end user.
This was first published in January 2003