Mmm... Oreo.
I use both ProE & SW. Patterning has always been one of those areas where I wish the two companies would borrow from each other. ProE can do exactly what you're asking because it can pattern any dimension, not just the location of a feature. If the location/sizing is not uniformly distributed, all you would have to do is create a pattern table with two columns: one for the location of each Oreo, another for the size of the filling.
I wish ProE would implement SW's method for placing/patterning multiple holes. It's very efficient to visually locate all the holes on a surface by dimensioning points in a 2D or 3D sketch. This assists greatly in maintaining design intent. ProE on the other hand forces you to create one hole and use a pattern to locate the rest. If you want to keep your holes equidistant from the edges of a rectangular plate, you'll have to use relations to control your pattern table parameters. It gets messy.
Anyhow, I'm done ranting and being minimally helpful. I agree with the others. The closest thing to a real solution is probably to create configurations of the filling. Each config could be a different BOM entry. Good luck.