Hi absMing,
I'm not sure I understand. If you write code, you can do whatever you want. In general, best practice is to map your form's main data source to one primary table. You can have multiple foreign key table updates too, but mapping a main data source to multiple tables is a non-standard practice and will cause you grief.
Patrick Halstead [InfoPath MVP]
InfoPathDev
Patrick Halstead
Project Manager at Qdabra