Report subscription with smart filter

I provide data on surgical site infections to a few parties within my organization. I want to be able to subscribe them to a weekly update email from PowerBI. I record the date that an infection is added to the dataset in a column on the report that the Dataset uses. I found a way to filter my report on "relative date", which is almost what I need, except when I create an automatic weekly update with that filter on it, the link takes my people to the report filtered on the 7 days prior to the day that they are actually viewing the report instead of the 7 days prior to the day the weekly subscription email was sent! I need a way to set the filter on the weekly subscription email to the 7 days prior to the reminder, not the 7 days prior to whatever day it happens to be when the link is clicked!