Because of the way CMOD 'packages' the documents that it stores, you would have to extract the load, modify the file to remove the unwanted documents, reload it, then remove the old load in order achieve what you want.
Alternately, you could use the Enhanced Retention Management module with implied holds, then remove the implied hold from the document you no longer wish to keep, and only the documents with holds would be kept at reclamation time, effectively achieving the document deletion.
Check with your information management team or legal department on how much effort & cost you should invest in this.
-JD.