How can we make auto invoice to work WITHOUT distinct interface_line_attribute values?

Hi,

We are on R12.1.3. We want to establish AR invoices using auto invoice program. But the problem is all of them have the same information except the customer and of course Bill To.

Auto invoice is failing for error "This line has the same transaction flexfield as another row in the interface table.For each transaction line, the combination of interface_line_context and interface_line_attribute values must be unique."

Can anyone of you please suggest how can we go ahead with given such constraint?

Thanks.

Anil