No, it is not possible to restrict a particular Departments for selected Customer Portal users. Once a Department is made "Public", all Customer Portal users can access that particular Department.
Yes, you can restrict certain agents from deleting the requests by setting up permissions in the respective agents profiles. Please goto Setup >> Admin Settings >> Profiles. In the Profile setting page, edit the profile and uncheck the Delete ...
You can restrict Delete Permission by setting the Profiles under Setup > Admin Settings > Profiles. You can either edit the default Standard Profile or add a new Profile and un-check Delete options for the modules and save the Profile. Now, associate ...
You can restrict this at Profiles. Goto Setup >Admin Settings >Profiles Edit the standard profile or create a new profile and un-check the option Customize Zoho Support under Admin Options. Associate this Profile to the Support Agent (Setup >Admin ...