Supplier as a customer in R12

Dear all,

I think we can treat supplier as a customer in R12. But how we can receipt cheque in receivables as a customer(supplier).

Actually , We paid some amount to our suppliers as a cheque and he returned us in shape of cheque , then we can receive cheque in receivables against the customer,

how system can understand dual function, supplier as a customer.

Please provide step by step documents if someone has.

Thanks