Define Project Hierarchy for Project Contracts

Hi All

When we are creating the Contract, we want to define the Master Project code in Header level and SUb projects in Contract Lines Level. I checked it in Oracle document that we can define our hierarchies and we can use different Project codes in Line level. There is no option to define the hierarchy and use them in Contract Authoricing.. How do we define the Project hierarchy in OKE so that we can use that fin Project Contracts?

Regards

Rajkumar