Big Box Retailer Ordering Woes

SUGGESTED

We sell bins of mixed product to big box retailers.  We purchase and inventory those bins as 1 item number, but the stores will only order the individual eaches that make up the bin.  For example, 

Bin D is equal to 

100 Part A

200 Part B

300 Part C

The store will order parts a b and c and expect to get Bin D.  Is there a way to make this conversion work in Sage 500? As it stands the order comes in EDI and we have to manually adjust and then manually adjust back the invoice going out and it's not working well.