Batch Determination in Process Order with respect to purchase price

In our industry several batches are purchase in different prices. Upon creating process order we have to maintain budget control over receipe. We need to incorporate summarize total of all selected batch to determine whether we are within budgeted price or not.

For e.g.

Receipe

Component Qty Purchase Price total Price Batch No

Component A 12 KG 105 Per KG 12*105 = 1260 1245450

Component B 5 KG 90 Per KG 90*5 = 450 15124

Total 17 KG 1710

AVG Price Per KG = 1710 / 17 = 100.58

We have a control that receipe should not be exceed to total 100 Per KG.

Can some help me in this regard that how can I get these details at the time of creation of process order.

Note : if receipe not in range we will change batch to get it under control.