Exclude Condition once reach target quantity

Dear guru,

I include one pricing Condition type in our pricing procedure ,because my client customer supplying some child parts to my client (example: 500no's) ,so they r using that child part to produce the final part , so we deduct that child part value from finished product price , one we consumed 500 quantity i need to remove that condition automatically

give me the solution

Regards

U.Maha