Not essentially, I mean you can request support team to enable the secondary custom dedupe criteria for the particular source type say list import/form fill, etc. Whatever you choose, it then applies to all leads that come in through that method. Also, It must be an EXACT match. (For instance, if I chose email address and first name as my criteria, it looks at the EXACT name and email for deduping. If that first name was ever missing, a new lead would be created for that record), Lastly, one of the secondary dedupe criteria must be the email address. The other (or multiple) can be anything you want, a standard or custom field. Your primary dedupe criteria then will apply to all the other source types, i.e., for the source types for which you do not have the secondary dedupe set. While at first this may seem solution most of your problems, if not all, but trust me this when enabled w/o proper strategy and plan to organize/maintain your DB would eventually turn in a headache down the line.