Using Git Hook on specific branches or maybe merge requests

We’re considering upgrading to Gitlab EE and I’ve been looking into the Git Hook feature and love the idea of forcing a MERGE REQUEST into MASTER to have at least one comment related to a Jira issue. What I’d not like to do is force every commit to contain a jira issue number. I could even see requiring the merge itself to have a jira number.

When I look at the documentation online, it really seems like it forces every commit to have a jira ticket and I’d like to avoid that level of scrutiny. Is that possible in EE?