diff --git a/README.md b/README.md
index 66a00e7..82c6554 100644
--- a/README.md
+++ b/README.md
@@ -105,10 +105,10 @@ Sample REST API calls:
 
 * Send a message to a group
 
-  ```curl -X POST -H "Content-Type: application/json" -d '{"message": "Hello World!", "number": "<number>", "group_id": "<group id>"}' 'http://127.0.0.1:8080/v1/send'```
+  ```curl -X POST -H "Content-Type: application/json" -d '{"message": "Hello World!", "number": "<number>", "recipients": ["<group id>"], "is_group": true}' 'http://127.0.0.1:8080/v1/send'```
 
   e.g:
 
-  ```curl -X POST -H "Content-Type: application/json" -d '{"message": "Hello World!", "number": "+431212131491291", "group_id": "ckRzaEd4VmRzNnJaASAEsasa"}' 'http://127.0.0.1:8080/v1/send'```
+  ```curl -X POST -H "Content-Type: application/json" -d '{"message": "Hello World!", "number": "+431212131491291", "recipients": ["ckRzaEd4VmRzNnJaASAEsasa"], "is_group": true}' 'http://127.0.0.1:8080/v1/send'```
 
 In case you need more functionality, please **file a ticket** or **create a PR**
diff --git a/doc/HOMEASSISTANT.md b/doc/HOMEASSISTANT.md
index 071085c..cdffbc1 100644
--- a/doc/HOMEASSISTANT.md
+++ b/doc/HOMEASSISTANT.md
@@ -46,5 +46,33 @@ e.g:
 
 ```curl -X POST -H "Content-Type: application/json" 'http://127.0.0.1:8080/v1/register/+431212131491291/verify/123-456'```
 
+
+## Sending messages to Signal Messenger groups
+
+The `signal-cli-rest-api` docker container is also capable of sending messages to a Signal Messenger group.
+
+Requirements: 
+
+  * Home Assistant Version >= 0.109
+  * signal-cli-rest-api build-nr >= 2
+    The build number can be checked with: `curl -X GET -H "Content-Type: application/json" 'http://127.0.0.1:8080/v1/about`
+  * your phone number needs to be properly registered (see the "Register phone number" section above on how to do that)
+
+A new Signal Messenger group can be created with the following REST API request:
+
+```curl -X POST -H "Content-Type: application/json" -d '{"name": "<name of the group>", "members": ["<member1>", "<member2>"]}' 'http://127.0.0.1:8080/v1/groups/<number>'```
+
+e.g:
+
+This creates a new Signal Messenger group called `my group` with the members `+4354546464654` and `+4912812812121`.
+
+```curl -X POST -H "Content-Type: application/json" -d '{"name": "my group", "members": ["+4354546464654", "+4912812812121"]}' 'http://127.0.0.1:8080/v1/groups/+431212131491291'```
+
+Next, use the following endpoint to obtain the group id: 
+
+```curl -X GET -H "Content-Type: application/json" 'http://127.0.0.1:8080/v1/groups/<number>'```
+
+The group id then needs to be added to the Home Assistant `configuration.yaml` file (see [here](https://www.home-assistant.io/integrations/signal_messenger/) for details)
+
 # Troubleshooting
 In case you've problems with the `signal-cli-rest-api` container, have a look [here](TROUBLESHOOTING.md)
diff --git a/src/main.go b/src/main.go
index 5a744d4..2ab0a5c 100644
--- a/src/main.go
+++ b/src/main.go
@@ -32,18 +32,23 @@ func cleanupTmpFiles(paths []string) {
 }
 
 func send(c *gin.Context, attachmentTmpDir string, signalCliConfig string, number string, message string,
-	recipients []string, base64Attachments []string, base64EncodedGroupId string) {
+	recipients []string, base64Attachments []string, isGroup bool) {
 	cmd := []string{"--config", signalCliConfig, "-u", number, "send", "-m", message}
 
-	if base64EncodedGroupId != "" && len(recipients) > 0 {
-		c.JSON(400, gin.H{"error": "Please specify either a group id or recipient(s) - but not both"})
+	if len(recipients) == 0 {
+		c.JSON(400, gin.H{"error": "Please specify at least one recipient"})
 		return
 	}
 
-	if len(recipients) > 0 {
+	if !isGroup {
 		cmd = append(cmd, recipients...)
 	} else {
-		groupId, err := base64.StdEncoding.DecodeString(base64EncodedGroupId)
+		if len(recipients) > 1 {
+			c.JSON(400, gin.H{"error": "More than one recipient is currently not allowed"})
+			return
+		}
+
+		groupId, err := base64.StdEncoding.DecodeString(recipients[0])
 		if err != nil {
 			c.JSON(400, gin.H{"error": "Invalid group id"})
 			return
@@ -212,7 +217,7 @@ func main() {
 	router.GET("/v1/about", func(c *gin.Context) {
 		type About struct {
 			SupportedApiVersions []string `json:"versions"`
-			BuildNr int `json:"build"`
+			BuildNr              int      `json:"build"`
 		}
 
 		about := About{SupportedApiVersions: []string{"v1", "v2"}, BuildNr: 2}
@@ -288,7 +293,7 @@ func main() {
 			Recipients       []string `json:"recipients"`
 			Message          string   `json:"message"`
 			Base64Attachment string   `json:"base64_attachment"`
-			GroupId          string   `json:"group_id"`
+			IsGroup          bool     `json:"is_group"`
 		}
 		var req Request
 		err := c.BindJSON(&req)
@@ -302,7 +307,7 @@ func main() {
 			base64Attachments = append(base64Attachments, req.Base64Attachment)
 		}
 
-		send(c, *signalCliConfig, *signalCliConfig, req.Number, req.Message, req.Recipients, base64Attachments, req.GroupId)
+		send(c, *signalCliConfig, *signalCliConfig, req.Number, req.Message, req.Recipients, base64Attachments, req.IsGroup)
 	})
 
 	router.POST("/v2/send", func(c *gin.Context) {
@@ -311,7 +316,7 @@ func main() {
 			Recipients        []string `json:"recipients"`
 			Message           string   `json:"message"`
 			Base64Attachments []string `json:"base64_attachments"`
-			GroupId           string   `json:"group_id"`
+			IsGroup           bool     `json:"is_group"`
 		}
 		var req Request
 		err := c.BindJSON(&req)
@@ -321,7 +326,7 @@ func main() {
 			return
 		}
 
-		send(c, *attachmentTmpDir, *signalCliConfig, req.Number, req.Message, req.Recipients, req.Base64Attachments, req.GroupId)
+		send(c, *attachmentTmpDir, *signalCliConfig, req.Number, req.Message, req.Recipients, req.Base64Attachments, req.IsGroup)
 	})
 
 	router.GET("/v1/receive/:number", func(c *gin.Context) {