diff --git a/lib/logster/message.rb b/lib/logster/message.rb
index d0549da5..a04e95ae 100644
--- a/lib/logster/message.rb
+++ b/lib/logster/message.rb
@@ -113,7 +113,8 @@ def self.default_env
 
     # in its own method so it can be overridden
     def grouping_hash
-      { message: self.message, severity: self.severity, backtrace: self.backtrace }
+      message = self.message.gsub(/[0-9a-f]+/i, "X")
+      { message: message, severity: self.severity, backtrace: self.backtrace }
     end
 
     # todo - memoize?
diff --git a/test/logster/test_redis_store.rb b/test/logster/test_redis_store.rb
index 0d252ea7..bab2b12c 100644
--- a/test/logster/test_redis_store.rb
+++ b/test/logster/test_redis_store.rb
@@ -1044,6 +1044,24 @@ def test_truncated_messages_when_they_are_similar_can_still_be_merged
     end
   end
 
+  def test_messages_that_differ_only_by_numbers_or_hashes_are_merged
+    config_reset(allow_grouping: true) do
+      first_message = <<~TEXT
+        DistributedMutex("download_20450e291e8f1e5ba03ca7f20fb7d9da570c94a6"):
+        held for too long, expected max: 60 secs, took an extra 73 secs
+      TEXT
+      msg = @store.report(Logger::WARN, '', first_message, backtrace: caller)
+
+      second_message = <<~TEXT
+        DistributedMutex("download_e09ae082c60a351dedec67ed869652862b232a0b"):
+        held for too long, expected max: 60 secs, took an extra 287 secs
+      TEXT
+      msg2 = @store.report(Logger::WARN, '', second_message, backtrace: caller)
+
+      assert_equal(msg.key, msg2.key)
+    end
+  end
+
   private
 
   def config_reset(configs)