Nowadays a high planning flexibility is required due to customer-driven markets and a rising number of product variants. In context of a supply chain this flexibility is also important for the procurement of input parts from external suppliers. In this work a method for simultaneous production and order planning in a cooperative supply chain relationship is presented. The method is part of an overall approach which tries to coordinate order quantities of an input part using flexibility contracts. Thereby the input part is delivered by two suppliers for which frame contracts with quantity and quota agreements exist. The objective is to guarantee these quantities in the frame contract horizon at minimum costs. A fine planning approach is presented which plans the production of the manufacturer simultaneously with the orders for the considered input part under consideration of priory defined flexibility corridors.