I want to track a variable which is populated by the IT team on a page. How do I keep a watch of that variable availability using DTM? which function need to be used?

How to identify which PostEvent (of a WKF Activity) has trigged a External Signal of other workflow?I have more than 1000+ WKF's, and I am not able to identify which WKF is triggering the external signal of a particular WKF? There is no unique identifier for the External Signal activity, to know how it triggered. Also, display logs of External Signal Activity doesn't give much information of who had triggered.