diff --git a/test/check-group-unknown.mjs b/test/check-group-unknown.mjs
new file mode 100644
index 0000000..12a027b
--- /dev/null
+++ b/test/check-group-unknown.mjs
@@ -0,0 +1,51 @@
+import { initTestEnv } from './init-test-env.mjs';
+import { getEnvKey, setEnvKey } from '../tools/lib/envkeys.mjs';
+import { fetchProject } from '../tools/lib/project.mjs';
+import { validateSession } from '../tools/lib/validate.mjs';
+import * as assert from 'node:assert';
+
+async function fetchTestProject() {
+  return fetchProject(
+    await getEnvKey('PROJECT_OWNER'),
+    await getEnvKey('PROJECT_NUMBER'));
+}
+
+describe('Validation of unknown groups', function () {
+  before(function () {
+    initTestEnv();
+    setEnvKey('PROJECT_NUMBER', 'group-unknown');
+    setEnvKey('ISSUE_TEMPLATE', 'test/data/template-group.yml');
+  });
+
+  it('takes mapping into account regardless of type abbreviation (BG -> Business Group)', async function () {
+    const project = await fetchTestProject();
+    project.chairsToW3CID = { 'The Super Business Group': -1 };
+    const sessionNumber = 1;
+    const errors = await validateSession(sessionNumber, project);
+    assert.deepStrictEqual(errors, []);
+  });
+
+  it('takes mapping into account regardless of type abbreviation (BG -> BG)', async function () {
+    const project = await fetchTestProject();
+    project.chairsToW3CID = { 'The Super BG': 'ok' };
+    const sessionNumber = 1;
+    const errors = await validateSession(sessionNumber, project);
+    assert.deepStrictEqual(errors, []);
+  });
+
+  it('takes mapping into account regardless of type abbreviation (Working Group -> Working Group)', async function () {
+    const project = await fetchTestProject();
+    project.chairsToW3CID = { 'the not heavily working group': 'lazy' };
+    const sessionNumber = 2;
+    const errors = await validateSession(sessionNumber, project);
+    assert.deepStrictEqual(errors, []);
+  });
+
+  it('takes mapping into account regardless of type abbreviation (Working Group -> WG)', async function () {
+    const project = await fetchTestProject();
+    project.chairsToW3CID = { 'the not heavily WG': -1 };
+    const sessionNumber = 2;
+    const errors = await validateSession(sessionNumber, project);
+    assert.deepStrictEqual(errors, []);
+  });
+});
\ No newline at end of file
diff --git a/test/data/group-unknown.mjs b/test/data/group-unknown.mjs
new file mode 100644
index 0000000..db1b164
--- /dev/null
+++ b/test/data/group-unknown.mjs
@@ -0,0 +1,15 @@
+export default {
+  description: 'meeting: Mapping of unknown group names, timezone: Etc/UTC, type: groups',
+
+  sessions: [
+    {
+      number: 1,
+      title: 'The Super BG'
+    },
+
+    {
+      number: 2,
+      title: 'The Not Heavily Working Group'
+    }
+  ]
+}
\ No newline at end of file
diff --git a/tools/lib/groups.mjs b/tools/lib/groups.mjs
index 857ec8f..a864c21 100644
--- a/tools/lib/groups.mjs
+++ b/tools/lib/groups.mjs
@@ -16,7 +16,13 @@ import { fetchW3CGroups } from './w3c.mjs';
 export async function fetchSessionGroups(session, groups2W3CID) {
   const lcGroups2W3CID = {};
   for (const name of Object.keys(groups2W3CID ?? {})) {
-    lcGroups2W3CID[name.toLowerCase()] = groups2W3CID[name];
+    const normalized = name.toLowerCase()
+      .replace(/ Business Group$/i, ' bg')
+      .replace(/ Community Group$/i, ' cg')
+      .replace(/ Interest Group$/i, ' ig')
+      .replace(/ Working Group$/i, ' wg')
+      .replace(/ Task Force$/i, ' tf');
+    lcGroups2W3CID[normalized] = groups2W3CID[name];
   }
 
   const w3cGroups = await fetchW3CGroups();