T-SQL (SS2K8) :: Matching Existence Of Data Between Like Columns?

I've been matching some incoming contacts to existing contacts in a database and need to update, insert, or rematch based on the ifs below.

If name, phone, and email all provided for both, then use the highest Source. So if the Contact has a Source value of 5 and SourceContact has a ContactSource of 1, update Contact with SourceContact

If name, phone and email all provided, and source the same then update to new values.

If name and phone on SourceContact and name and Email on Contact then reset Contact_fk to -1 should not have matched, but should be an insert

If name and email on SourceContact and name and phone on Contact then reset Contact_fk to -1 should not have matched, but should be an insert

If name and phone on SourceContact and name and/or Phone is blank in Contact then update

If name and email on SourceContact and name and/or email is blank in Contact then update

If phone numbers can be different, just update record to SourceContact if it has a same or higher ContactSource

If email address do not match then set SourceContacts to -1 Contact_fk it was computed incorrectly. Both have a non blank email

If Contact_fk is 0 then it is a new contact and just insert it.

IF OBJECT_ID('dbo.SourceContact', 'U') IS NOT NULL DROP TABLE [dbo].[SourceContact];
CREATE TABLE [dbo].[SourceContact]
(
[SourceContact_pk]INT IDENTITY(1,1) NOT NULL CONSTRAINT PK_SourceContact PRIMARY KEY CLUSTERED,
[ContactLastName] VARCHAR(30) NOT NULL CONSTRAINT DF_SourceContact_ContactLastName DEFAULT (''),
[ContactFirstName] VARCHAR(30) NOT NULL CONSTRAINT DF_SourceContact_ContactFirstName DEFAULT (''),

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