Purchase requisitions and Purchase orders require routing based approvals.

How can we achieve the approval requirement below in Oracle Cloud?

The client is currently using PeopleSoft, and they are having a approval routing functionality which works as below:

All the approvers have the same role. When Buyer 3 submits the requisition, it should only go to Approver B, even though all the approvers have the same role. We cannot use supervisory hierarchy approval since the Approver is not the Manager/Supervisor of the buyer.