Currently the system mandates which key fields are used during a mass import of data.  It would be helpful if the user could select the key field and/or have a sequential order that the system uses to check for duplicates (ie, first look at last name, if same then look at email address, etc.)  We are finding lots of new records are created because the system isn't looking at the right markers or in a logical way (Joe Smith at 123 Main is the same person as Joseph Smith at 123 Main, etc.)