I would like to create groups of approvers. Though it is possible to set up a multi level workflow approval, the system does not allow to do it by creating groups. i.e.

1) Sales representatives create purchase order which should be approved by sales manager (1st approver) and then to finance manager (2nd approver).

2) Marketing representative create purchase order which should be approved by marketing manager (1st approver) and then to finance manager (2nd approver).