Trigger Pipelines in Multiple Azure DevOps Projects from a single Repository in Github

Question

As the title already suggests, we're struggling to find out how we can trigger pipelines in multiple DevOps projects in the same DevOps organization from a single GitHub repository.

The GitHub webhooks were automatically added by DevOps when we configured our first pipeline trigger via the button that appears in the Trigger Tab (it says "Restore" as it doesn't find the correct webhooks in Github).

What we've done:

• We've connected our repository to all projects via dedicated Service Connections
• Each push to the main branch will trigger all pipelines in all projects
• When we open a PR, only the pipelines in the project where we've clicked the button "Restore" button are triggered.
• The button to auto-configure the webhooks only appears if there are no webhooks configured in Github, so we can't do this for all of our projects.
• We also can't do it manually, as we don't know the secret that is used by DevOps within the webhooks.

Any help or tip in the right direction will be immensely helpful!