Pay when Paid using a "draw number"

When there are 10 subs on a job, billing various times a month, we are unbale to tie all these invoices together. When we bill the owner various times, I need a way to mark them all with 1 unique number, aka "draw number' so when we get paid, we then know what subs to pay. Currently, we are unbale to mark various invoices, from different subs, using the same unique number; this way, when we get paid, this unique/draw number reflects payments made and we can pay our subs.