Vendor Partner Fucntion Question

Hi Experts,

We have the following scenario and how to handle this?

We have a main vendor (parent vendor). We won't create PO at this level.

We have goods supplier associated to the above main vendor. PO and GR at this stage. I understand by SAP partner function OA and GS we can handle this.

We have a different remit to (Invoicing Party) for the above main vendor *** goods supplier. I understand by SAP partner function PI we can handle this.

But the question is, during MIRO, we want the PI should come automatically? Business dont want to enter this manually. Can this be possible?

Do we have any SAP standard report for this partner function. I mean we need to know at main vendor level, how much we spent / purchase?

Thanks

RS