I am curious if a vet can file for bipolar after bieng diagnosed with ptsd. The va grouped the depression and ptsd together. Isn't bipolar a different disorder. Any advice

Yes you can and yes it is a separate condition.
http://forums.military.com/eve/forums/a/tpc/f/4230026980001/m/1440001270001

Here is some information from the American Psychiatric Association on bi-polar symptoms. It may be a little tricky to read, but if you take your time, you will find that bi-polar diagnoses are quite different than PTSD or Acute Stress Disorder.

Thanks for your posting and hopefully this will be helpful to you and to others.