How to create targets form a master list of leads

We have a master list of leads (about 20M records)

We run email marketing campaigns to small subsets of the list on a weekly basis.

Is there a way to create a marketing campaign with associated targets that are permanently tied to the leads list - so that we can track which records we have “touched” with email over time and with what results?

Waht is the recommended best practice for this type of scenario?