diff --git a/src/firefighter/incidents/models/group.py b/src/firefighter/incidents/models/group.py
index 6c1da4c..6c3b3e3 100644
--- a/src/firefighter/incidents/models/group.py
+++ b/src/firefighter/incidents/models/group.py
@@ -7,6 +7,7 @@
 
 
 class Group(models.Model):
+    """Group of [Components][firefighter.incidents.models.component.Component]. Not a group of users."""
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     name = models.CharField(max_length=128, unique=True)
     description = models.TextField(blank=True)
diff --git a/src/firefighter/incidents/models/incident.py b/src/firefighter/incidents/models/incident.py
index 373e0f6..5c65c03 100644
--- a/src/firefighter/incidents/models/incident.py
+++ b/src/firefighter/incidents/models/incident.py
@@ -53,7 +53,7 @@
 logger = logging.getLogger(__name__)
 
 if TYPE_CHECKING:
-    from collections.abc import Sequence  # noqa: F401
+    from collections.abc import Iterable, Sequence  # noqa: F401
     from decimal import Decimal
     from uuid import UUID
 
@@ -460,7 +460,7 @@ def build_invite_list(self) -> list[User]:
         users_list: list[User] = []
 
         # Send signal to modules (Confluence, PagerDuty...)
-        result_users: list[tuple[Any, Exception | list[User]]] = (
+        result_users: list[tuple[Any, Exception | Iterable[User]]] = (
             signals.get_invites.send_robust(sender=None, incident=self)
         )
 
diff --git a/src/firefighter/slack/admin.py b/src/firefighter/slack/admin.py
index 0b81af1..aa7b7fa 100644
--- a/src/firefighter/slack/admin.py
+++ b/src/firefighter/slack/admin.py
@@ -189,8 +189,45 @@ class MessageAdmin(admin.ModelAdmin[Message]):
 class UserGroupAdmin(admin.ModelAdmin[UserGroup]):
     model = UserGroup
 
+    list_display = [
+        "name",
+        "handle",
+        "usergroup_id",
+        "is_external",
+        "tag",
+    ]
+
+    list_display_links = [
+        "name",
+        "handle",
+        "usergroup_id",
+    ]
+
+    readonly_fields = (
+        "created_at",
+        "updated_at",
+    )
+
     autocomplete_fields = ["components", "members"]
-    search_fields = ["name", "handle", "usergroup_id"]
+    search_fields = ["name", "handle", "description", "usergroup_id", "tag"]
+
+    fieldsets = (
+        (
+            ("Slack attributes"),
+            {
+                "description" : ("These fields are synchronized automatically with Slack API"),
+                "fields": (
+                    "name",
+                    "handle",
+                    "usergroup_id",
+                    "description",
+                    "is_external",
+                    "members",
+                )
+            },
+        ),
+        (_("Firefighter attributes"), {"fields": ("tag", "components", "created_at", "updated_at")}),
+    )
 
     def save_model(
         self,
diff --git a/src/firefighter/slack/migrations/0002_usergroup_tag.py b/src/firefighter/slack/migrations/0002_usergroup_tag.py
new file mode 100644
index 0000000..f95b587
--- /dev/null
+++ b/src/firefighter/slack/migrations/0002_usergroup_tag.py
@@ -0,0 +1,22 @@
+# Generated by Django 4.2.16 on 2024-10-14 10:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("slack", "0001_initial_oss"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="usergroup",
+            name="tag",
+            field=models.CharField(
+                blank=True,
+                help_text="Used by FireFighter internally to mark special users group (@team-secu, @team-incidents ...). Must be empty or unique.",
+                max_length=80,
+            ),
+        ),
+    ]
diff --git a/src/firefighter/slack/models/user_group.py b/src/firefighter/slack/models/user_group.py
index 6f8eae6..f3b7f66 100644
--- a/src/firefighter/slack/models/user_group.py
+++ b/src/firefighter/slack/models/user_group.py
@@ -174,6 +174,12 @@ class UserGroup(models.Model):
         help_text="Incident created with this usergroup automatically add the group members to these components.",
     )
 
+    tag = models.CharField(
+        max_length=80,
+        blank=True,
+        help_text="Used by FireFighter internally to mark special users group (@team-secu, @team-incidents ...). Must be empty or unique.",
+    )
+
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
 
diff --git a/src/firefighter/slack/signals/get_users.py b/src/firefighter/slack/signals/get_users.py
index 3f7fdfa..05efb59 100644
--- a/src/firefighter/slack/signals/get_users.py
+++ b/src/firefighter/slack/signals/get_users.py
@@ -8,20 +8,22 @@
 
 from firefighter.incidents import signals
 from firefighter.incidents.models.user import User
+from firefighter.slack.models.user_group import UserGroup
 from firefighter.slack.slack_app import SlackApp
 
 if TYPE_CHECKING:
+    from collections.abc import Iterable
+
     from django.db.models.query import QuerySet
 
     from firefighter.incidents.models.incident import Incident
     from firefighter.slack.models.conversation import Conversation
-    from firefighter.slack.models.user_group import UserGroup
 
 logger = logging.getLogger(__name__)
 
 
 @receiver(signal=signals.get_invites)
-def get_invites_from_slack(incident: Incident, **_kwargs: Any) -> list[User]:
+def get_invites_from_slack(incident: Incident, **_kwargs: Any) -> Iterable[User]:
     """New version using cached users instead of querying Slack API."""
     # Prepare sub-queries
     slack_usergroups: QuerySet[UserGroup] = incident.component.usergroups.all()
@@ -39,4 +41,28 @@ def get_invites_from_slack(incident: Incident, **_kwargs: Any) -> list[User]:
         )
         .distinct()
     )
-    return list(queryset)
+    return set(queryset)
+
+
+@receiver(signal=signals.get_invites)
+def get_invites_from_slack_for_p1(incident: Incident, **kwargs: Any) -> Iterable[User]:
+
+    if incident.priority.value > 1:
+        return []
+
+    if incident.private:
+        return []
+
+    slack_usergroups: QuerySet[UserGroup] = UserGroup.objects.filter(
+        tag="invited_for_all_public_p1"
+    )
+
+    queryset = (
+        User.objects.filter(slack_user__isnull=False)
+        .exclude(slack_user__slack_id=SlackApp().details["user_id"])
+        .exclude(slack_user__slack_id="")
+        .exclude(slack_user__slack_id__isnull=True)
+        .filter(usergroup__in=slack_usergroups)
+        .distinct()
+    )
+    return set(queryset)