Prospect Management: Best Way to Cross-Check New Hires Contacts Against Those of Current Sales Staff???

Prospect Management: Best Way to Cross-Check New Hires Contacts Against Those of Current Sales Staff???

I'm sure I'm not the only one in this situation so hope this can answer any questions Sales Managers have as they build out their teams.

The Skinny:  I just hired two new sales staff to build our direct business.  Both of them have extensive lists of contacts from over their careers and we'd like to utilize them as best as possible.  However, there is bound to be overlap with the Ad Agencies, Brands and/or People they know.  

I need to determine the best way for them to utilize the ZOHO CRM platform when inputting the prospects they plan to contact so that:
  1. I can identify areas of overlap.  Right now, they populate "Potentials" for any contact they may reach out to.
  2. Once they made initial outreach to the people they've listed in "Potentials" and used the "BCC to Zoho" function to track emails/leads, they're not creating data entry redundancies.  I'd like to know the best way for them to list their prospects prior to initial outreach such that once they contact them and use BCC function, it connects to the information they'd entered previously in Zoho.
I hope this makes sense.

Thanks
Evan