Referral Tracking

I see there have been several posts about referral tracking. My organization relies heavily on referral sources to manage our prospective company pipeline. A Referral would be separate from a Contact as Contacts are generally employees within the prospective company. I have setup Referral as a custom field in the Prospects module however I am trying to find a way to manage my referral network, logging various calls and touch points I have with them, and the conversion rates of their referred Prospect companies. Any ideas?