Help with my gallery (levels question)

I’m having trouble jumping back and forth between levels in the gallery i’m creating. If you look at the my picture, clicking on the bottom row of buttons loads a ‘picture group’ into the right side container (called container2). Then I want to be able to click on the numbers in the picture group to load a new picture into the left side container (called container).
From the bottom row, I can load things into the left container fine, and into the right container fine, but then not from the right container to the left. Make sense? Any help is appreciated.