CI/CD: Deploying to multiple environments after MR

I am learning how to setup pipelines to deploy to a certificate Kubernetes cluster, already connected & associated with my GitLab project. Here’s how I have things setup:

I have two namespaces:

  • Staging

  • Production

I have two branches:

  • Staging (deploys to staging)

  • Master (deploys to production)

The developers create feature branches and submit merge requests. After approval/merge, the changes are deployed to the target branch of the merge request (usually staging). Following testing on the staging environment, I would like the same merge request to be deployed to our master branch to make the feature available to customers.

Is there a way to target multiple branches with a single merge request? If not, how do you handle similar situations? Does the developer need to submit another merge request with master being the target?