How to set a relationship between work orders in MRP?

Hi everyone,

I need to see the relationship work orders for in MRP/MPS planning. For example, parent work order will be created with MPS for finished goods, after we run MRP for semi-finished goods and these will be child work orders of parent work orders. MRP calculates complete requirement and creates one work order for every semi finished item codes. And they dont want to use fixed order quantity, because it multiplies by a fixed batch. This is very important for us, do you have a soution for this?

Thanks.