Delegate security

Dear all,

We are an international company with HQ in the Netherlands.
The ICT is centrally arranged and our intention is to implement a central helpdesk/asset database.

Currently I've setup Regions, Sites and Departments.

I want to be able to delegate control for e.g. Asset management to my USA administrator (Region) and my German administrator (Site).

How to set this up?

Regards,

Ralph