Exchange Global Acces List and iOS 5

Hi,

since I upgraded my iPhone 4 to iOS 5, I feel bad with the management of the contacts of my corporate email (exchange email).

With iOS 4 I had my address book with my contacts synced with iTunes (I tried syncing with Google Sync, but I did not like that the fields were often different). When I wanted to access the global access list of my work corporate, it was enough for me to go to "Groups --- > Exchange Address List" and there was all the corporate directory, online (not synced).
Now this capability no longer exists, as I can't see the "Groups" button in the contact app. This happens even disabling iCloud and still using the synchronization with iTunes.

To activate the "Groups" button in the contact app, I need to enable the contact synchronization with corporate email. But I don't want to do this beacuse I don't want to mix my private contacts with the company ones.
One solution would be: activate an exchangemailbox(hotmail or gmail for example) leaving blank the address book, and activate thesynchronizationwithiPhone ofthis mailbox. This will enable the button in the contacts and groups would have access also to other sections of the Exchange account configured on the phone. I hope I was clear.
Someone is having the same problems and some ideas for a better solution?

Thank you.