"Vendors" Added to New "Lookup" Field Type?

"Vendors" Added to New "Lookup" Field Type?

I wanted to add a new field for my "Leads" tab called "Currently Using" and then tie that into competitor's information that I have stored in the "Vendor" tab (which I've renamed as "Vendor or Competitor").

However, when I selected "Lookup" as the Field Type, "Vendors" is not available as a "Lookup Type." Is there anything I can do to get this added?

Thanks!
Kris Thomason