Restricting User for PO release

Hi,

I would like to restrict user for PO Release on the basis of Plant for example

Plant

Approver to Receive Email Notification

1010

AJINDAl1

1020

KJINDAL1

1110

GJINDAL1

1120

RSULLIV1

So For Plant 1010 only AJINDAL1 can release this PO ,

How & Where I can implement this functionality.

Thanks

Ankesh Jindal