Ways to handle BU specific approval groups

We have a few hundreds of business units and the requisition and purchase order approval needs to be forwarded to the corresponding CEO, CFO, CTO etc. of the specified BU. To support requirements like this, we define rules like the below

if Requisition BU = BU A and amount > X, then require approval from group CFO of BU A

if Requisition BU = BU A and amount > Y, then require approval from group CFO +CEO of BU A

if Requisition BU = BU A and category = IT, then require approval from group CTO of BU A

if Requisition BU = BU B and amount > X, then require approval from group CFO of BU B