MRP for STO & Purchasing

Dear experts,

Please could you please advise if it is possible to customize MRP in order to be runned as described :

We have Material 1 in Storage location 001, plant 100

The requirement is to have Material 1 in storage location 002, plant 100, through STO, else Purchasing.

Example :

Material 1 in Sloc 001, plant 100 : Quantity = 10

MRP generates need of 30 in Sloc 002, plant 100 : Quantity = 20

So here, i would like to have STO of quantity 10, then 10 of standard purchase order.

Thanks a lot of advise.

Cheers