cocoa - Autolayout constraint where height is the sum of sub view heights -

Is it possible to create an autolyout hurdle, where the height of a scene is the sum of its Sun's visible height?

I have a design where sub-view 1 and sub-view 2 are stacked vertically in one scene. Sub-view 1 is a certain height, but sub-view 2 should be able to alternate between zero altitude and its content height

Autolayout is killing me for this < P>

If you want to force one in the form of a supervision to look at the top of sub-view 1, Below the lower part it is a hindrance in the lower part of a supervision of the barrier format str Ng would look like this:

  @ "V: | [Sbwu 1] [Sbwu 2] |"   
 This will also create hindrances which are touching subview1 and suvbview2, which is probably what you want.