Corps Attachments Now Possible?

[MisterMark]

In the current scenario I'm playing, there is only one Corps HQ on the map... he's fixed and according to the reinforcement schedule, it doesn't look like any other Corps will be arriving in the scenario. 

So does that make the option of 'corps attachments now possible' not possible in my current game?  You would need at least 2 Corps on the map (and at least one division) to take advantage of corps attachments, correct? 

Or can corps attachments happen between other levels of command?  Say for instance, reassigning a regiment/brigade to a different division or reassigning a battalion to a different regiment/brigade?

-Mark