Set up virtual PC to access non-trusted domain?

I have a user who is wearing two hats.  She now works at two different companies which are part of the same corporation.  Each company has its own domain, email server, etc.  We'd like to be able to allow her to access the other company's domain when she is at either plant.

Originally I was thinking of having a duel boot system whereby she could boot into an OS partition that was set up for the domain of the plant she was at.  But this solution doesn't allow her access to the resources of the other domain at the other company (resources like email).

What I was thinking of was having a virtual PC environment set up on a duel boot PC so that when she was booted up under a given OS set up for a given domain she could also set up a virtual PC session into the OTHER domain and thereby access her email and other services there.

Is this possible?

Rich