Articulate Presenter 13 - Changing Slide Levels for Hierarchical Menu

I'm hoping someone can help me.  In Articulate Presenter '09 you could go into Slide Properties and there would be a Level column that you could assign to slides (e.g. 1, 2 , 3, etc).  This would dictate how your slides would present in the menu Outline.  But in Presenter '13 this Level column no longer appears.

I know in Presenter '13 I can click the  Edit Menu button to enter Player Properties and then use the left / right arrows to indent the slides so they appear as sub-levels (i.e. expandable in the menu by clicking the preceding 'parent slide's' triangle).

The problem is I have a really huge presentation of 700 plus slides (yes I know not great - but before any of you make comment about the size of this document, I hasten to add it is a technical specs document rather than training/e-learning program and I have no control over the content - only preparing and publishing it).  So to use the arrow key to indent each menu option is going to be super tedious and time consuming, and I haven't yet found how to do it for multiple slides at same time.

So I'd really appreciate someone's help.  I presume the programmers would have considered this and come up with something - if they have I can't seem to find it.

Gracias, Michael