I have created a menu item the I want to show a list of items from 3 sub categories.  
I have chosen "Order" in the menu parameter "item ordering".  But I can't figure out what order method it is using.  What I get is subcategoryA item 1, sub-catB item 1, sub-catC item 1, sub-catA item 2, sub-cateB item 2, etc

It appears to be combining the sub categories and the order by K2 item list order.

I want it to list all the:
sub-catA items 1-7, 
then sub-catB items 1-5, 
then sub-catC items 1-5.

How do I control the order of the items from multiple categories?