Check out this clip from Planning Center University.
In the Approval Groups tab on the People page, click the New Approval Group button.
Name the new approval group, and then search for people to make them approvers in the group. A person must have permissions in Calendar to be an approver and can be added to any number of approval groups.
Members are not notified when they're added or removed from an approval group.
Once you've created an approval group, you can add it to rooms, resources, and event request forms. One person from each approval group will need to approve requests for anything that group is assigned to.
Open the settings for a room or resource and select Add approval group. Each room and resource can have multiple approval groups assigned to it.
Event Administrators will assign a default approval group when an event request form is created. Each event request form can only have one approval group assigned to it.
On the Approval Groups tab of the People page, you can view and edit your existing approval groups. Expand sections in an approval group to view its members and see which rooms, resources, and event request forms its members are responsible for.
Members, rooms, and resources can be added to the approval group in the approval group settings. Edits to approval groups in event request forms must be done in the event request form's settings.