Gating implementation in GIT Lab


How would you recommend to implement customized gates in GIT Lab?
As i understand the GIT Lab manual, the CI/CD feature is not relevant for teams who use Jenkins.

I do see that the Jenkins plugin for GIT Lab can provide status as pipeline to merge requests. However, what i miss is the ability for derived gates from the build to initiate their own pipelines and register in the merge request.
Is there any relevant API to achieve that?