I've not been able to do this but the best I can suggest is that you use a generic name for the resource, for example designer1, designer2 etc. Using a custom field or the notes in the resource information panel note the resources actual name. When you display the plan use the resource group field instead of the resource name field and the audience, who ever that maybe, will only see the group not the named resource but you will have the information that gives you the name in the background.
Hope this helps.
Will