REST API Post rows to dependent table?

I have created a dataset via REST that has four tables: A, B, C, D. Table B has a dependent relationship on A, and D has a dependent relationship on B & C.

I wrote a program to load the data in the following order: A, C, B, D. The program loads A & C fine, but times out trying to load B. When I remove the relationships all four tables load fine.

Is there a better way to load dependent tables?