Do you care to share a bit more of what you're trying to accomplish here? I think what you're trying to do is technically possible, but it seems kind of unconventional.
Are you hoping for Developers to create product rules which encapsulate a change request and its creation would automatically trigger a pipeline? Our deployment manager product provides a similar workflow using branches. If you have special requirements where you want to define your own pipeline you may also consider creating a simple case type which the developer provides a product rule and triggers a build.
If you want to design something just as you described I think you have two potential options:
Use the pyPostSave extension point in the Rule-Admin-Product class to trigger the pipeline.
Create a declare trigger in the Rule-Admin-Product class to trigger the pipeline.
Using both of these options you can define your own criteria around when a build should be triggered.