Greg,
I'm guessing by "converted" you're referring to SFDC records that have been converted from a Lead to a Contact/Account/Opportunity.
You could create a segmentation to distinguish which are "converted" and which aren't by using the SFDC Type smartlist criteria.
Converted will be SFDC Type = Contact
Non-converted will be SFDC Type = Lead or empty
Let me know if you were looking for something else.