Currently you'll have to check access in edit templates for stuff like this.
There is an old patch around to add policy checks to attributes, but no idea when something like this might be part of eZ Publish out of the box. There is also the possibility that policy limitation on class attribute category(4.3 feature) is implemented instead, but both cases would solve your case without having to hard code business logic in templates.
If security is important for you (not sure it is with a department, but whatever), you could also use the same configuration as you would use the customize the template inside a workflow event and reject data that doens't match 'em.
Such a configuration could look like this:
[global]
; XXX is the Communication department's content object ID
AttributePermissions[XXX]=all;deny
AttributePermissions[XXX]=keywords;allow
