Vista - Vista and hosts file usage

Here's my issue. Our company has a Windows Server 2003 domain. We have
begun purchasing new laptops with Windows Vista. We have an application (SQL
Express based) loaded on the laptops that our staff use when they go to
clients. The staff create peer to peer networks at the client site using
hubs and cables. We use static alternate ip addresses for the peer to peer
networks and maintain a common hosts file to provide name resolution for the
application. In Windows XP this worked fine without any problems. Now in
Windows Vista we have problems with computers when they are connected to our
network (not peer to peer but to the domain) where Vista is using the hosts
file to resolve the local computer name to the alternate ip address instead
of using the DNS services provided by our domain. This doesn't happen in
Windows XP. As a result we have to remove the each individual Vista machine
from the hosts file so our application will work when they are in the office.
This means that instead of maintaining 1 hosts file that is distributed to
each machine we must maintain individual hosts files for each computer and
update them all manually when we add a new computer. Does anyone know why
Vista behaves this way? Is it intentional? Can it be changed? Maintaining
50+ hosts files will be an administrative nightmare.

Any insight or help on this issue would be greatly appreciated!

Thanks