how can I Deploying multiple projects to the same repository

How can I trigger the deployment of a vercel project only when code changes are made in a subdirectory?

I have a repository with three subdirectories of that corresponds to vercel’s three projects, now every time I push the code will trigger the deployment of the three projects, I want to in which subdirectory there is a change in the code, the corresponding project repository before triggering the deployment, what should I do?

when i try the Ignored Build Step feature, it tell me:

Configuration Settings in the current Production deployment differ from your current Project Settings.