(Jenkins/GitLab) Webhook triggered when a user is assigned

In GitLab, I have made it so that when a Merge Request is created, it triggers Jenkins which builds the source branch.

(This is how I did it: In GitLab, I’ve added a webhook on a Merge Request, and in Jenkins, I’ve configured it to accept merge requests)

Problem is, if there’s an Open Merge Request, and after a while someone assigns a user to that Merge Request, that will trigger the webhook and it will build the Jenkins job again, even though it’s not necessary.

Is it possible to not have the Jenkins job triggered when a user is assigned to the GitLab Merge Request? (I couldn’t find anything online and in Jenkins, it looks exactly the same in terms of the build and environment variables)

Thanks ahead!