How intercept xorigin changes after an unsubscribe

Hi all,

I need to intercept the update of field xorigin on PersonHasEset when a PWO is unsubscribed.
I explain better my need:

A person may have a system role connected directly and indirectly from itshop.
When the system role is unsubscribed from ITshop, after some time the value of Xorigin change from 3 to 1.
I need to intercept this change.
I try to check the Event Update on PersonHasEset but it seems that not intercept this case.

If there is the process that update the xorigin after an unsubscribe I can add a step on this process.
There are others way to intercept this change ?
Thank you very much and best regards