Subform linked to another subform

[Scott]

I have a form with three subforms in datasheet view. The form
contains data from a Customer table. The first subform contains data
from a Model table that is linked to the Customer form. The second
subform contains data from an Interface table that is linked to the
Model subform. The third subform contains data from a Service table
that is also linked to the Model subform. When I scroll through the
Customer form, the Model subform scrolls accordingly. When I scroll
through the Model subform, the Interface subform scrolls accordingly;
however, the Interface subform always displays the record for the
first record in the Model subform. The "Link Master Fields" and "Link
Child Fields" are the same for both the Interface subform and Service
subform.

The relationship for the tables are as follows:
Customer - CustomerID
Model - CustomerID, ModelID
Interface - ModelID, InterfaceID
Service - ModelID, ServiceID

Can someone point out my blind spot?

My humble regards,
Scott