Is this layout possible to do with omega and how?

Based on the cont-sidebar1.png attached file , is it possible to nest sidebar second region inside the content region? and can set the height of the sidebar.

There is an image view above the text content (a block) .When there are just few images this will be the layout (cont-sidebar1.png) but when some images are added the text content will go below the sidebar and get the full width of the content-region ( see layout cont-sidebar2.png.)

Your help is greatly appreciated :)
thank you