Tracking hits from mailer

Content

We recently sent a mass mailing out through a third party vendor and we want to track the number of times that potential applicants hit the link in the mailer.  I tried using the # Hits field, but it aggregates the number over several Req. Source Types.  Am I approaching this the right way?  Could we also just ask the third party vendor for the number of hits from their side?

Thanks,

Megan