How to get the domain an intranet user is coming from?

Hi,
We are using IIS6 and .Net Framework 2.0 for our intranet with Windows and Digest Authentication . We have 2 domains that have access to this intranet. I suddenly have the need to  display slightly different content for users from Domain A. The changes are rather trivial (text on a label and and image in a header) but important to our stakeholders.
Can you tell me if this information is available within asp.net? Would the Current.User or some other object provide access to this?
 
Thanks for your help
 
 
...