How to import customer site contact only

Target: only import customer site contact

(1) fill in customer and contact tabs in simplifyed customer template

(2) fill in account and site information in contact type

Results

i.e one customers contains one account, one account contains 30 Sites

Each site contains one contact (email), The account contains 30 contact from Sites

This creates confusion in account as there are many contact information in account. Therefore, please advise how to import site contact only for sending dunning letter.