How to make ByDesign consider available stock from another site before creating a Purchase Proposal

[Rathapol]

Hello SAP Community,

I’m encountering a planning issue in SAP Business ByDesign related to multi-site stock consideration

Scenario Overview

We have one product maintained in two Planning Areas under the same Planning:

Site Planning Area Procurement Type Available Stock Demand Behavior

Site A (Headquarter)	HQ	External Procurement	0 ea	7 ea	System created Purchase Proposal for full 7 ea
Site B (Secondary Site)	RY	Internal Procurement	1 ea	—	Stock available but not considered

Current System Behavior

Type Source Quantity (ea) Comment

Purchase Proposal	External Supplier	7	Created in Site A
Stock Transfer Proposal	AGRY0000 → AGHQ0000	—	Not created
Total Supply		7	All from external source

Expected Result

Type Source Quantity (ea) Comment

Stock Transfer Proposal	AGRY0000 → AGHQ0000	1	Should use available stock first
Purchase Proposal	External Supplier	6	For remaining demand
Total Supply		7	Covers total requirement in Site A

The system should first consider available stock from another site,
create a Stock Transfer Proposal, and then generate a Purchase Proposal for the remaining quantity.

What setup or configuration is required so that ByDesign can:

1. Consider available stock from another site,

2. Automatically create a Stock Transfer Proposal, and

3. Create a Purchase Proposal only for the remaining demand?