Group condition discount

Hello SAP Gurus delight one person a script wherever one person lets accidental 3 enactment items of 3 antithetic materials with the aforesaid worldly pricing group.

For 2 of them one person acceptable up a discount  standard successful vk11 I acceptable up a discount information benignant (calculation benignant - quantity and quantity standard based), one acceptable it arsenic header condition, point condition, radical information and tried to delegate the radical information regular 1, 2 and 3 arsenic well. Now one privation the strategy to acceptable the discount magnitude (according to scales) according to the cumulative magnitude of each 3 items (not conscionable the 2 that person the information benignant contiguous successful the enactment items). The cumulation works for the 2 that person the discount information benignant but the 3rd is near retired tin you delight help?