Create 1 main purchase order per project

The desire is to be able to create one main purchase order, link an X amount to it, and then link product lines to it.
They want to subdivide this main purchase order into X number of purchase orders, and then add a component or part of a product line from the main purchase order under each purchase order. For example, if there is 100m2 of flooring to be laid, they want to be able to link 20m2 to a specific purchase order and also see in the main purchase order that there is still 80m2 left to be outsourced and to see how much has actually been carried out.
They would also like to receive a notification if they create a partial purchase order and want to add X number of a product line and exceed what is planned in the main purchase order, informing them that what they want to write on the purchase order is not possible because they have planned X number for this part.