I had a Groupwise account for a few years, I never did figure out the proper settings to get direct access of email on my Blackberry. My work around was to set the account to forward all email to my BB account. Groupwise would leave the original copy on the mail server, so it would be there once I logged in from a computer. I still received notifications but was unable to reply directly without logging in on either the mobile site or from a desk. At the time, notification was more important than me replying.
Once we switched over to Outlook and Exchange, life became much easier with the official email.