"Division" comes as default based upon selected "Department"

Summary

How to make Depertment a dependent field, based upon selected Division

Content

By default, Division field is not displayed on any page. When we add Division field on a custom page, this is shown as default field; and we cannot select divisions. A default Division is shown, based upon the selected Department.

We want to make Department field, dependent upon selected Division. If there a way where by Department can be made dependent upon Division?

Furthermore, we have cases where same department exists in more than on Division e.g. Accounts department exists in all of our Divisions. Is there as way to define a sort of Shared Services concept?