Editing Item Types

Is it possible to edit multiple item types at once?

I have multiple .cel files with multiple models within each that all have a common item type "manufacturer". I would like to edit some of the "manufacturer" for some .cel files, without changing all of them by changing it in the dgnlib file. Is there an easier way to do this rather than going into each model in each .cel file and clicking on each item to then edit its item type info?