Vendor and Multiple Locations

Dear Gurus,

I have the following scenarios where required gurus feedback.

I have a Vendor and have its sub location almost 30-40, when I receive the GRN at that time I come to know about the actual location from where I receive the stock.

Is there any possibility to maintain the sub location vendor in main vendor partner function or at PO header level, so that system ask the correct one at the time of GRN.

I can not in a position to open the multiple PO for the same Vendor because of its different location.

Please guide me how i can configure the above scenario, invoicing party in the main vendor only.

thanks.