OK, I may misunderstand the question but here goes.
First off, _if_ you create a pool of four drives, _why_ would you _not_ want files in certain "Folders" to be distributed over the four drives? Put otherwise, _what_ is it that you want to pool the drives for? It seems to me that what you want to accomplish is, basically, having four seperate physical and logical drives.
I am not familiar with Drive Bender but I assume that DB will (like Drive Pool) assign a drive letter to a logical drive, the logical drive being the Pool. You should (and would with DP) see all files in the shared folder _provided_ that the mapping of the share points to the actual Pool (and not a similarly named folder on one of the drives), that is, the logical drive created by DB / DP that represents the Pool (and therefore all four drives).
But the basic question is, what is it that you want the pool to do for you?