diff --git a/src/codemodder/result.py b/src/codemodder/result.py
index 8dd66c55..99293601 100644
--- a/src/codemodder/result.py
+++ b/src/codemodder/result.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import itertools
 from abc import abstractmethod
 from dataclasses import dataclass, field
 from pathlib import Path
@@ -139,7 +140,14 @@ def fuzzy_column_match(pos: CodeRange, location: Location) -> bool:
 
 
 class ResultSet(dict[str, dict[Path, list[Result]]]):
+    results_for_rule: dict[str, list[Result]]
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.results_for_rule = {}
+
     def add_result(self, result: Result):
+        self.results_for_rule.setdefault(result.rule_id, []).append(result)
         for loc in result.locations:
             self.setdefault(result.rule_id, {}).setdefault(loc.file, []).append(result)
 
@@ -157,6 +165,16 @@ def results_for_rule_and_file(
         """
         return self.get(rule_id, {}).get(file.relative_to(context.directory), [])
 
+    def results_for_rules(self, rule_ids: list[str]) -> list[Result]:
+        """
+        Returns flat list of all results that match any of the given rule IDs.
+        """
+        return list(
+            itertools.chain.from_iterable(
+                self.results_for_rule.get(rule_id, []) for rule_id in rule_ids
+            )
+        )
+
     def files_for_rule(self, rule_id: str) -> list[Path]:
         return list(self.get(rule_id, {}).keys())
 
@@ -164,16 +182,22 @@ def all_rule_ids(self) -> list[str]:
         return list(self.keys())
 
     def __or__(self, other):
-        result = ResultSet(super().__or__(other))
+        result = self.__class__()
         for k in self.keys() | other.keys():
-            result[k] = list_dict_or(self[k], other[k])
+            result[k] = list_dict_or(self.get(k, {}), other.get(k, {}))
+        result.results_for_rule = list_dict_or(
+            self.results_for_rule, other.results_for_rule
+        )
         return result
 
+    def __ior__(self, other):
+        return self | other
+
 
 def list_dict_or(
     dictionary: dict[Any, list[Any]], other: dict[Any, list[Any]]
-) -> dict[Path, list[Any]]:
-    result_dict = other | dictionary
+) -> dict[Any, list[Any]]:
+    result_dict = {}
     for k in other.keys() | dictionary.keys():
-        result_dict[k] = dictionary[k] + other[k]
+        result_dict[k] = dictionary.get(k, []) + other.get(k, [])
     return result_dict
diff --git a/tests/test_results.py b/tests/test_results.py
index e8c7c832..7e697765 100644
--- a/tests/test_results.py
+++ b/tests/test_results.py
@@ -55,6 +55,11 @@ def test_or(self, tmpdir):
             in combined["python:S5659"][Path("code.py")]
         )
 
+        assert combined.results_for_rules(["python:S5659"]) == [
+            result1["python:S5659"][Path("code.py")][0],
+            result2["python:S5659"][Path("code.py")][0],
+        ]
+
     def test_sonar_only_open_issues(self, tmpdir):
         issues = {
             "issues": [