AME Approval for iproc requisitions

 Hello Experts,

Can anyone please advice on the below scenario.

Currently we are following the Employee Supervisor Hierarchy. On a requisition from a user, it will be going to his immediate supervisor for approval. 

User ------->  Supervisor

Now requirement is like this.

User ---> Materials Department ----> Finance Department ----> Supervisor.

I have set an AME and it is not working as expected.

Advice on How should I define AME so it will include the two between levels as above and follow the employee Supervisor hierarchy.

Your help is very much appreciated.

Thanks

Vivek