If you don't need the additional classification, but intend on using just one for your products, then changing the values from resources is the easiest solution. Just go to Sitefinity backend -> Administration->Interface labels&Messages and look for the resource keys related to Department (use the searchbox we've provided in that screen to get all applicable keys, and plurals as well). You will then be able to specify custom values for these keys. Once you're done please restart your application so the new resource entries can be read from the configuration. If any issues occur, just let us know, we'll be glad to help.
the Telerik team
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