Single Payment Receipts against multipule customer invoices

Hi All,

I need your help to slove this business senario, here i have one payment receipts i need to clear against multiple customer invoice, how to clear the single payment receipt for multiple customer invocies,

But customer will not infore which invoice should be clear first. system will pick automatically and clear invoices as per First in first out method.

how i process this soultion.

thanks

Kiran