advanced pricing link discount to item purchase

I'm trying to come up with a way to discount some accessory items, if the customer purchases a machine item.  i.e., purchase item A (a machine) at full price, receive a 10% discount on items B, C and D (accessories for the machine).  Is there a way to do this?  I could even fake it if I could come up with a way to make it work, for example I could set this up based on an order level threshold.  If you spend $1000(example machines would cost this or more), items B, C and D receive a 10% discount.  I've