Stumped by Object Style issue

Hi, I am ready to jump out a window with this one. I have an object style applied to two text frames (image attached), which applies a stroke and shading, auto-size, fixed width. One style is for a single column, one is for a double column.

I can't apply these attributes in the paragraph styles, because in the double column, it treats the text as two single columns, and doesn't apply shading and a stroke in the gutter.

However, I can't offset the bottom stroke in the object style, which means the shading in that style projects below it. Adjusting inset spacing in the object style has no effect.

I'm an experienced ID user, but not an expert. This has me absolutely stumped. And frankly, close to tears with frustration. Any ideas?