diff --git a/src/main.c b/src/main.c
index 88666ba..1ef007e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -64,6 +64,7 @@ static void signal_cb(struct ev_loop *loop, ev_signal *w, int revents)
 }
 
 static struct option long_options[] = {
+    {"group",       required_argument, NULL, 'g'},
     {"id",          required_argument, NULL, 'I'},
     {"host",        required_argument, NULL, 'h'},
     {"port",        required_argument, NULL, 'p'},
@@ -84,6 +85,8 @@ static struct option long_options[] = {
 static void usage(const char *prog)
 {
     fprintf(stderr, "Usage: %s [option]\n"
+            "      -g, --group=string       Set a group for the device(Any printable character except\n"
+            "                               space is allowed, with a maximum of 16 characters)\n"
             "      -I, --id=string          Set an ID for the device(Any printable character except\n"
             "                               space is allowed, with a maximum of 32 characters)\n"
             "      -h, --host=string        Server's host or ipaddr(Default is localhost)\n"
@@ -118,7 +121,7 @@ int main(int argc, char **argv)
 #define SSL_SHORTOPTS ""
 #endif
 
-    const char *shortopts = "I:i:h:p:d:aDt:f:RS:vV"SSL_SHORTOPTS;
+    const char *shortopts = "g:I:i:h:p:d:aDt:f:RS:vV"SSL_SHORTOPTS;
     struct ev_loop *loop = EV_DEFAULT;
     struct ev_signal signal_watcher;
     bool background = false;
@@ -150,8 +153,15 @@ int main(int argc, char **argv)
             break;
 
         switch (c) {
+        case 'g':
+            if (!valid_id(optarg, 16)) {
+                log_err("invalid group\n");
+                return -1;
+            }
+            rtty.group = optarg;
+            break;
         case 'I':
-            if (!valid_id(optarg)) {
+            if (!valid_id(optarg, 32)) {
                 log_err("invalid device id\n");
                 return -1;
             }
diff --git a/src/rtty.c b/src/rtty.c
index 45521bc..1790785 100644
--- a/src/rtty.c
+++ b/src/rtty.c
@@ -369,6 +369,9 @@ static void rtty_register(struct rtty *rtty)
     len += rtty_put_attr_u8(wb, MSG_REG_ATTR_HEARTBEAT, rtty->heartbeat);
     len += rtty_put_attr_str(wb, MSG_REG_ATTR_DEVID, rtty->devid);
 
+    if (rtty->group)
+        len += rtty_put_attr_str(wb, MSG_REG_ATTR_GROUP, rtty->group);
+
     if (rtty->description)
         len += rtty_put_attr_str(wb, MSG_REG_ATTR_DESCRIPTION, rtty->description);
 
diff --git a/src/rtty.h b/src/rtty.h
index 1fa5b69..b027141 100644
--- a/src/rtty.h
+++ b/src/rtty.h
@@ -61,7 +61,8 @@ enum {
     MSG_REG_ATTR_HEARTBEAT,
     MSG_REG_ATTR_DEVID,
     MSG_REG_ATTR_DESCRIPTION,
-    MSG_REG_ATTR_TOKEN
+    MSG_REG_ATTR_TOKEN,
+    MSG_REG_ATTR_GROUP,
 };
 
 enum {
@@ -96,6 +97,7 @@ struct rtty {
     const char *host;
     int port;
     int sock;
+    const char *group;
     const char *devid;
     const char *token;        /* authorization token */
     const char *description;
diff --git a/src/utils.c b/src/utils.c
index 1295d43..029cc9c 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -48,9 +48,9 @@ int find_login(char *buf, int len)
     return -1;
 }
 
-bool valid_id(const char *id)
+bool valid_id(const char *id, size_t limit)
 {
-    if (strlen(id) > 32)
+    if (strlen(id) > limit)
         return false;
 
     while (*id) {
diff --git a/src/utils.h b/src/utils.h
index a1dcbdf..1562836 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -30,7 +30,7 @@
 
 int find_login(char *buf, int len);
 
-bool valid_id(const char *id);
+bool valid_id(const char *id, size_t limit);
 
 int b64_encode(const void *src, size_t srclen, void *dest, size_t destsize);