diff --git a/dlibrary/dlibrary.py b/dlibrary/dlibrary.py
index c4dbfba..ec567ed 100755
--- a/dlibrary/dlibrary.py
+++ b/dlibrary/dlibrary.py
@@ -212,6 +212,9 @@ def complete_prefix_number_ordering(entries):
     unified_indices = list(unified_indices)
     unified_indices.sort()
 
+    if len(unified_indices) > 1 and min(unified_indices[i] - unified_indices[i-1] for i in range(1, len(unified_indices))) > 2:
+        return None
+
     versions = list(numberings_by_version.keys())
     versions.sort()