Nanda, you are correct, DSO 1 has a GL Account and DSO does not. DSO 1 is the GL Line item DSO and DSO 2 is the Tax table for Accounting Documents which dosen't contain the GL Account. However, the 2 DSO's do have account document number, company code, document type and period in common.
Basically, I'm trying to create a new DSO that will only hold that data for a specific set of GL Accounts (DSO 1). DSO 2 contains the tax information along with some customer information that I need to update the existing records with. However, the way its set up i'm loading everything from the 2nd DSO since I dont' have a way to restrict the data.