Sharing Scheduled report only for PDP based alert trigger

We are trying to implement a PDP based alert system that can schedule reports only for the users whose PDP data qualifies the alert rule. On a PDP enabled dataset, we tried setting the alert in Contextual mode, but the alert trigger is considering total dataset to validate the alert rule and sharing the report with everyone in the subscriber list. When we tried to set the alert with a specific PDP policy, the alert is not being triggered either at a user level or the entire dataset level even when the numbers qualify for the alert rule. Any thoughts on how to set-up the alert and Scheduled Report to achieve this functionality?