Hi,
The task was really good, and would have to say your answer lies with a simple concept of IDP that is Peer port Modulator. When Peer port modulator is enabled, if any of the interfaces goes down with respect to Vr , then the sensor will automaticly make all the interface with respect to Vr will be down and obviously then the appropriate action wil take place.
You can go through with the below KB.
KB7418
Please accept as a solution if it really helps you.