Apply Receipt for an AR invoice ( Two separate customers)

There is a particular AR invoice where it has come from a customer and the receipt for the same invoice is received from another customer. How can i apply the receipt to the invoice.

Eg : AR invoice is raised for "ABC" Customer , the cash is received for the same invoice from "TTT" customer.("ABC" and "TTT" customers have a link)

       So how can i apply the Receipt to the invoice. Please give a solution.