Categorising invoices in SAP

Dear all,

I am currently facing a problem as my customers want me to bill other parties for certain charges. For example, my customer Z's invoice has lines items A, B, C and D. The customer will only pay A and B. C and D will have to be collected from another company, say Y. Is it possible for me to add this additional information in SAP so that it will automatically bill Y instead of Z?