how to restrict PR document type to Purchasing organization

Hi experts,

I need your support, we need to restrict PR document type to Purchasing Organization .

for example we have document type DNB is for Purchase organiostion SDPO and Document type NB is for Purchasing organization SEPO. but what happen if user select Doc. type DNB and put SEPO as a purchasing organisation then system show no error but from company point of you it should be ERROR. So Please we required ur support fot that, if DNB is with SEPO it shows ERROR and for DNB is with SDPO it is OK. viceversa for NB documnet type.

Thanks in Advance..