Purchase order release stretegy

Dear All,

We want to implement workflow for PR and PO release strategy. It will be very helpful to us for using Fiori Apps for releasing PR/PO.

1. PR Release :

Fist Release : We have department wise HODs.

Final Release : Plant Heads (more than one position)

2. PO Release :

First release : We have 2-3HODs (Purchase Dept, RM Procurement etc.),

Second Relase : Commercial Head, . RM Procurement Head

Final Release : VPs of Commercial and RM Procurement dept.

What will be the best way to implement ?

Thanking you