Hi
Presumably you specifed the operation on _contact1 to be "Update existing or create new". The trick then is to set up some match criteria that allows you to identify the primary contact uniquely. For example (source and target expression in the Match tab for _contact1):
normcomp(#sourceCompanyName) normcomp(#COMPANY)
This will compare the field "sourceCompanyName" in the incoming record with the COMPANY field in the _contact1 table. The normcomp() function is used to lowercase, trim, remove punctuation, and remove "noise" wrods such as "inc", "incorporated", "llc" etc.
Another type of match might be an unique company identifier stored in a key field.
What ever criteria you use, it is important to remember to write to that field when the record is created, so that subsequent matches will find the correct value.
I suggest you have a look at the tutorials on matching in the Resources section on the web site.
HTH
Regards
Admin