APO DP - Manage forecast for multiple items sharing same total forecast

Hello, I need your support to manage in APO DP the forecast calculation for different items sharing

the same total forecast.

Example for a 3 month period

                     M1     M2     M3

SKU 1  FC = 20     30      100          Promo code

SKU 2  FC = 30     50          0          Promo code

SKU 3  FC = 50     20          0          Regular code

Requirements is to:

1. Assign a predefined % split for the FC within the 3 SKUs in each month

(in M0 i'll then have the possibility to set already the 3 month split x SKU)

2. Having the system automatically taking into account the real sales in the

months to propose an adjusted FC % mix

Anybody having experience with an APO implementation for this topic?

Thank you very much for your support,

Gabriele