diff --git a/qurator/dinglehopper/ocrd_cli.py b/qurator/dinglehopper/ocrd_cli.py
index 89f04d9..1850eb1 100644
--- a/qurator/dinglehopper/ocrd_cli.py
+++ b/qurator/dinglehopper/ocrd_cli.py
@@ -34,11 +34,16 @@ class OcrdDinglehopperEvaluate(Processor):
         metrics = self.parameter['metrics']
         textequiv_level = self.parameter['textequiv_level']
         gt_grp, ocr_grp = self.input_file_grp.split(',')
-        for n, page_id in enumerate(self.workspace.mets.physical_pages):
-            gt_file = next(self.workspace.mets.find_files(fileGrp=gt_grp, pageId=page_id))
-            ocr_file = next(self.workspace.mets.find_files(fileGrp=ocr_grp, pageId=page_id))
+
+        input_file_tuples = self._zip_input_files([gt_grp, ocr_grp])
+        for n, (gt_file, ocr_file) in enumerate(input_file_tuples):
+            if not gt_file or not ocr_file:
+                # file/page was not found in this group
+                continue
             gt_file = self.workspace.download_file(gt_file)
             ocr_file = self.workspace.download_file(ocr_file)
+            page_id = gt_file.pageId
+
             log.info("INPUT FILES %i / %s↔ %s", n, gt_file, ocr_file)
 
             file_id = make_file_id(ocr_file, self.output_file_grp)
@@ -73,6 +78,24 @@ class OcrdDinglehopperEvaluate(Processor):
             # Clear cache between files
             levenshtein_matrix_cache_clear()
 
+    def _zip_input_files(self, input_file_grps):
+        log = getLogger('processor.OcrdDinglehopperEvaluate')
+        input_file_tuples = list()
+        for page_id in ([self.page_id] if self.page_id else
+                        self.workspace.mets.physical_pages):
+            ifiles = list()
+            for input_file_grp in input_file_grps:
+                log.debug("Adding input file group %s to page %s", input_file_grp, page_id)
+                files = self.workspace.mets.find_all_files(pageId=page_id, fileGrp=input_file_grp)
+                if not files:
+                    log.error('Found no page "%s" in file group %s', page_id, input_file_grp)
+                    ifiles.append(None)
+                else:
+                    ifiles.append(files[0])
+            if ifiles[0]:
+                input_file_tuples.append(tuple(ifiles))
+        return input_file_tuples
+
 
 if __name__ == '__main__':
     ocrd_dinglehopper()