Merge branch 'nagyv-gitlab-master-patch-89329' into 'master'

Added section about group level CI/CD tunnel

See merge request gitlab-org/gitlab!72302

doc/user/clusters/agent/ci_cd_tunnel.md

@@ -37,6 +37,12 @@ there isn't any context selected.
 Contexts are named in the following format: `<agent-configuration-project-path>:<agent-name>`.
 To get the list of available contexts, run `kubectl config get-contexts`.
 
+## Share the CI/CD Tunnel provided by an Agent with other projects and group
+
+The Agent can be configured to enable access to the CI/CD Tunnel to other projects or all the projects under a given group. This way you can have a single agent serving all the requests for several projects saving on resources and maintenance.
+
+You can read more on how to [authorize access to groups in the Agent configuration reference](repository.md#authorize-groups-to-use-an-agent).
+
 ## Example for a `kubectl` command using the CI/CD Tunnel
 
 The following example shows a CI/CD job that runs a `kubectl` command using the CI/CD Tunnel.