offline authentication

Hi,

   I need to authenticate users of an application against a windows 
domain, but I need it to work offline.
   I've used JCifs in the past (the web filter), so I'm used the API 
before.

   My first doubt is if it can be done. I know local workstations cache 
login credentials, is there a way to take advantage of this ?

   What I would really like to do is to obtain the logged user and his 
groups from JCifs, but last time I checked this wasn't possible. I also 
looked at jcifs-ext, but it seems stuck in time against jcifs 0.9.4.

   Thanks for any help.

Ricardo