PO approval based on which buyer raises a PO

Hi
We have set up procurement and AME for requisition approval. There are only 2 buyers say X(for IT purchases) and Y(other Purchases)
While approving PO we need the following

1. If X has raised the PO and is greater than 10000 USD then ITICS head will approve
2. If Y has raised the PO and is greater than 10000 USD the CFO will approve

All PO's less than 10000USD need to be approved by the respective buyer

How can this be achieved in Purchasing through approval groups


Thanks