Best Pratice of Handling Trade& Non-Trade ; Local & Foreign

Would like to ask for opinions that :
Whats the Best Pratice of Handling Trade & Non-trade ; Local & Foreign;
Currently ,
1. Trade & non trade is managed through Account Payable Account as
a. Trade Payables
b. Non-Trade Payables

2. Local & Foreign is managed through Vendor Category (Custom Field).This is critical because a vendor's classification (Local/Foreign) can change depending on the Subsidiary creating the bill.

The Core Challenges:

Upon Vendor Bill transactions, its required to determine Local & Foreign as for certain Subsidiaries , its defined as local; while others subsi should be defined as foreign;

Furthermore,

Upon Vendor Bill transactions, its required to manually determine Acct Payables Account also as 1 Vendor have traded trading items and non-trade items at the same time; To make scenario complicated, there are scenario, within 1 Vendor Bill, there are Trading item and non-trading item at the same time;