diff --git a/README.md b/README.md
index f21584a..b79fcb9 100644
--- a/README.md
+++ b/README.md
@@ -179,3 +179,32 @@ By default, files are compared after gzip compression, but it's possible to use
 ```yaml
 compression: "none"
 ```
+
+### Checking multiple bundles
+
+The action reuses the same comment each time it runs on a PR. In order to run the action multiple times against separate bundles for a single PR, you must provide a `comment-key` option, which the action will use to determine which comment to add or update for the run. The example below demonstrates this for separate "modern" and "legacy" bundles:
+
+```diff
+name: Compressed Size
+on: [pull_request]
+jobs:
+  modern-bundle-size-check:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: preactjs/compressed-size-action@v2
+      with:
+        build-script: "build:modern"
++       comment-key: modern
+
+  legacy-bundle-size-check:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: preactjs/compressed-size-action@v2
+      with:
+        build-script: "build:legacy"
++       comment-key: legacy
+```
+
+If you do not provide this key, the action will attempt to use (and therefore replace) the same comment for both bundles, hiding the output for whichever run finished last.
diff --git a/action.yml b/action.yml
index e3ea5f4..3ebf27e 100644
--- a/action.yml
+++ b/action.yml
@@ -42,6 +42,9 @@ inputs:
     default: '{**/*.map,**/node_modules/**}'
   cwd:
     description: 'A custom working directory to execute the action in relative to repo root (defaults to .)'
+  comment-key:
+    description: 'Optional key to include in the bot comment to allow for multiple bundle calculations to be posted in separate comments.'
+
 runs:
   using: 'node20'
   main: 'index.js'
\ No newline at end of file
diff --git a/src/index.js b/src/index.js
index 8d897a2..93d021d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -185,11 +185,13 @@ async function run(octokit, context, token) {
 		issue_number: pull_number
 	};
 
+	const commentKey = getInput('comment-key')
+
 	const comment = {
 		...commentInfo,
 		body:
 			markdownDiff +
-			'\n\n<a href="https://github.com/preactjs/compressed-size-action"><sub>compressed-size-action</sub></a>'
+			`\n\n<a href="https://github.com/preactjs/compressed-size-action"><sub>compressed-size-action${commentKey ? `::${commentKey}` : ''}</sub></a>`
 	};
 
 	if (context.eventName !== 'pull_request' && context.eventName !== 'pull_request_target') {
@@ -213,9 +215,10 @@ async function run(octokit, context, token) {
 		let commentId;
 		try {
 			const comments = (await octokit.issues.listComments(commentInfo)).data;
+			const commentRegExp = new RegExp(`<sub>[\s\n]*(compressed|gzip)-size-action${commentKey ? `::${commentKey}` : ''}</sub>`)
 			for (let i = comments.length; i--; ) {
 				const c = comments[i];
-				if (/<sub>[\s\n]*(compressed|gzip)-size-action/.test(c.body)) {
+				if (commentRegExp.test(c.body)) {
 					commentId = c.id;
 					break;
 				}