There seems to be either some confusion or missing info about your design here:
I have created a data base of customers and Customer Sites attached to Customers.
I created Relationships, (Customer Site to Site Product) - (Product Type to Site Product) - (Customer Site to Inspection Report)
If there are just two tables involved here, customers and customer sites, your relationship should be:
Customers::__pkCustomerID = Customer Sites::_fkCustomerID
but maybe there are more tables involved that you have not identiifed here...
For an explanation of the notation that I am using, see the first post of: Common Forum Relationship and Field Notations Explained