Can I create a new organization hierarchy?

No. All organizations within your deploying company are part of a large overarching global hierarchy. Therefore, you can't add new organization hierarchies. However, you can move existing organizations or attach new organizations to the existing hierarchy and create a new version of the hierarchy.

Once you have created a new version, specify the date from which the new version must become active. On the specified date, your new hierarchy version replaces the older hierarchy.