IF Function by dates historically

Hello,

I have agent level data and I want to view all KPI data historically by tenure.

Example: Tenure date for Agent X is 10/08/2018. If I filter my report any day prior to 10/08/2018 I should not see KPI data for Agent X. Tenure date could vary based on Agent and I need my report to only reflect KPI data when an agent has hit their tenure mark.

Agent X = Tenure Date 10/08/2018

Agent Y = Tenure Date 10/15/2018

Agent Z = Tenure Date 11/16/2018

If I filter my report to show data for the Month of October, my data must only show data for Agent X from 10/08/2018 - 10/31/2018 and Agent Y from 10/15/2018 - 10/31/2018. How do I create an IF function to populate only relative data for specific date, month, or year.

KPI Data

Agent Roster