How to Promote an Entire Action Group?

There is the old way and the new way to promote an action. The old way it's done is by adding the Promoted, PromotedCategory, PromotedOnly and PromotedIsBig properties to the action. The new promoted syntax is used by applying the actionref keyword. You can't mix the two syntaxes. After adding actions to the actions section, you can then promote those actions by adding them in the promoted area of the actions section like so:

area(Promoted)
{
  addafter(Category_Category8)
  {
    group("Post-processing")
    {
      Caption = 'Post-processing';
      actionref(PopulateCostCenter_Promoted; "Populate Cost Center")
      {
      }
      actionref(CustomerItemClearing_Promoted; "Customer Item Clearing")
      {
      }
    }
  }
}