Trigger TeamCity job when specific branch is merged to Master

Any DevOps who has been involved in some serious CI/CD pipeline architectures have met these particular requirements at least once in his life:

1. Detect hotfix* branches that are merged to Master
2. Detect feature* branches that are merged to Master
3. Automatically trigger a job if (1) is true

Although most build systems support this feature (I know for a fact that this is the case for Bamboo and Jenkins) and the methodologies are similar, this blogpost will focus on Teamcity, probably because I saw a lack of documentation on the matter.

Teamcity is notorious for being tricky! The only way to trigger merges is by listening to the commit messages. With this in mind, we will bake our commit messages to reflect our needs.

Assumptions:

We will assume that the commit message looks something like:
git commit -m "hotfix-*"

Trigger when HotFix branch merged to Master:

Trigger when Feature branch merged to Master:

In both cases, the VCS should be only monitoring the Master branch: