Histogram showing Issues Added to Epics

I have a backlog of issues that are getting added to different epics. I want to see a timeline / histogram of how each team is doing in getting all of their issues added to the new epics.

So basically I want to see the timeline with the count of issues with and without an Epic Link count. (I could alternatively use the count of issues with a specific Label (i.e. “Gantt”) since those epic issues are being tracked for visibility in a Gantt chart as well).

I currently have Rows = Time (Weekly) and Columns = Measures(Issue History) and Label(Gantt) and this Timeline shows the increasing issue count for issues with that label BUT it shows them added in the timeline on the date they were created and not the date the Label got added.

How do I make it only count it starting on the date the label was added?

Thanks
Matt