public void setParentMenuGroup(String newParentMenuGroup) {
		if (menuPath.length <= 1) {
			throw new IllegalStateException(
				"Cannot set the parent menu group for a menu item " + "that has no parent");
		}

		if (SystemUtilities.isEqual(parentMenuGroup, newParentMenuGroup)) {
			return;
		}

		MenuData oldData = cloneData();
		parentMenuGroup = newParentMenuGroup;
		firePropertyChanged(oldData);

		this.parentMenuGroup = newParentMenuGroup;
	}
See the description in {@link #getParentMenuGroup()}

@param newParentMenuGroup the parent group
Ghidra/Framework/Docking/src/main/java/docking/action/MenuData.java